It's probably easiest to consider the various interventions on their own terms and see what scholars have to say about them. I actually am not familiar with how Ike's biographers have come down on this and perhaps there is a unifying synthesis , but as a diplomatic historian I can speak to the historiography of those interventions.

Now, I would also quibble and say that Eisenhower's foreign policy doesn't consist solely of intervention. What I'm about to say doesn't cover the scope of his diplomacy in Europe, or for that matter some of his actions in the Middle East such as his handling of the Suez Crisis. I'm going to try and stick to "interventions," such as they are.

Disclaimer: Eisenhower isn't a drastically more interventionist American president than the norm. Truman had, after all, thrown all kinds of support to the Christian Democrats in Italy in 1948, worked to break strikes in the Marseille docks in the '40s to weaken French communist unions, and sent American troops into Korea. For that matter, American troops had intervened time and again in Latin America from the turn of the century onward. However, Eisenhower pays ever greater attention to the developing world.

South Vietnam: Eisenhower gets a lot of credit for his actions in South Vietnam because we have the obvious historical parallel a decade later: Eisenhower chooses not to deploy troops to save French colonialism. Yet he also refused to do so in part because Churchill wouldn't back an intervention. Instead, he supported the Geneva Accords and the division of the country.

Eisenhower was hardly unique in supporting this solution; he had brought support with Congress to find a noncommunist middleman, and he found one in Ngo Dinh Diem. But Diem is never able to really build a stable South Vietnam. Part of that was because he was so good at alienating the Buddhist majority of his new country, and also because he was unwilling to consider the land reforms that might have won him some meaningful support in an overwhelmingly rural country. His own autocratic and nepotistic rule certainly fuels a nationalist insurgency, which the United States will fully deal with after Eisenhower.

In any event, Eisenhower throws his weight behind Diem. He works to ignore the provision of the Geneva Accords which required an election to take place to unify the country, because he recognizes that Ho Chi Minh would win such an election. His solution is to funnel enormous amounts of aid to Diem, but this has the effect of setting off inflation in the country without bringing any real long-term prosperity. Much of this is because of Diem's own unwillingness to enact real reform, but what it means is that the U.S. is on the side of an unpopular government, and because of the fallacy of sunk costs, it is unwilling to back away from that ally and risk losing face.

Guatemala: The U.S. coup in 1954 is one of the most-studied moments of the Cold War, for fairly obvious reasons. To briefly recap: the United States backs a coup, codenamed OPERATION PBSUCCESS, that removes the leader of the country, Jacobo Arbenz, from power. Arbenz had alienated the United States with a land reform program that involved expropriating land from the United Fruit Company in 1951. Following an arms embargo against the country, it tries to secretly import weapons from Czechoslovakia, a communist country. This spurs a coup that removes Arbenz from power.

To my certain knowledge, the scholarly consensus is that the coup didn't advance American security concerns appreciably, and if anything they undermined American attempts to maintain its hegemony in Latin America. Latin American states had high levels of poverty, economic troubles (some of which related to American investment, and even where they didn't they could be linked in other ways; Americans had enforced price controls during WWII to maintain access to cheap resources, which didn't benefit Latin America at all), and underdevelopment. While there is a scholarly debate about whether or not Arbenz was a communist, his ideological orientation is ultimately irrelevant, because in the eyes of many it puts the U.S. on the side of regressive autocrats. Che Guevara was in Guatemala during the coup against Arbenz, and it reportedly turned him to the cause of armed struggle. Even Eisenhower likely recognized that the coup had been a setback in certain respects: he funneled aid to a leftist government in Bolivia because he feared that another right-wing coup would weaken the image of the U.S., and according to Stephen Rabe laid a lot of the groundwork for what became the Alliance for Progress (which in turn descended into support for repressive governments, but which had a lot of bright rhetoric about development initially).

Iran: In some ways, the Iran coup is judged even more harshly because it's such an important step toward the Iran Hostage Crisis and the contemporary problems between the U.S. and Iran. It's a tremendous success in the short-term: oil from the Persian Gulf is maintained, the U.S. gets to work with a reliably pro-U.S. leader who, until he falls from power, works nominally in support of the U.S. as a regional peacekeeper (though in turn sowing the seeds of a number of long-term problems: see Roham Alvandi's Nixon, Kissinger, and the Shah). But for many Iranians, the hated British are replaced by the Americans as a meddling imperialist power, which allows strong nationalists to make common cause with conservative religious factions. Ironically, Mossadegh, the leader who was removed from power in the 1953 coup himself was not a likely supporter of the communists. Part of his turn to the Tudeh (the Iranian Communist Party) was that the economic sanctions put in place by the British had successively alienated other domestic allies.

Lebanon: The U.S. intervention in Lebanon in 1958 is often overlooked because Lebanon continues on in a relatively stable fashion afterward; the civil war that tears the country apart doesn't come for another 17 years. Eisenhower deployed marines to restore the presidency of Camille Chamoun. Lebanon was a country whose political structure was divided between Muslims and Maronite Christians, the former of whom were interested in joining Nasser's United Arab Republic. The Sunni prime minister backs such a scheme, and because there had been a similar coup in Iraq that same year, Chamoun requests the presence of U.S. troops.

On balance, this wasn't a devastating intervention for U.S. interests, and I don't think the U.S. particularly damaged the situation. Lebanon's government was fundamentally fragile irrespective of Eisenhower, but it also kicks the can down the road in a certain sense: the political tensions between groups do eventually erupt. In any event, while Nasser wouldn't have turned aside a chance to incorporate Lebanon into his pan-Arab ambitions, he was not a communist. Eisenhower's move doesn't particularly endear him to the Arab world, with whom in all fairness there was never going to be an easy relationship (Israel complicates a great many things).

In any event, the intervention in Lebanon doesn't make the U.S. any safer in the Cold War.

Cuba: Eisenhower inherited Cuba, to a large extent. America had first invaded in 1898, made it a de facto protectorate for decades on end, and backed the government of Fulgencio Batista. Batista's second term was not a popular one, and apart from his corruption, he made the island a playground for the American mafia. This naturally fostered resentment among impoverished Cubans, and the revolution that removes Batista from power brings to power Fidel Castro, backed by Che Guevara.

Castro was less a committed communist than a committed nationalist, albeit one surrounded by Marxists (his friend Fidel, and his brother Raul). He initially tries to warm relations with the United States, and Eisenhower in turn adopts a wait-and-see approach. However, it founders on a few issues. At first, relations between the U.S. and Cuba were relatively neutral. But Castro’s actions eventually alienated the Americans. He recognized several of the Eastern European states and negotiated deals with the Soviet Union for aid and technical assistance, moves which led American politicians to fear he was following along Arbenz’ path. He requested that U.S. oil refineries begin processing Soviet oil on the island; when they refused, he nationalized them along with other businesses. This sets off a tit-for-tat exchange in which businesses are nationalized, and the U.S. freezes assets. In March of 1960, Eisenhower authorized the CIA to begin destabilizing the Cuban government, and by October, a total economic embargo of Cuba had been declared. This leads to a break of diplomatic relations.

Eisenhower authorizes the Bay of Pigs, though it's carried out under Kennedy's presidency. From any perspective, it's a miserable disaster. Contrary to the hopes of planners in the CIA, there was no popular uprising to support the invading exiles, who without air support from the U.S. are trapped on the beaches and forced to surrender. The U.S. is left with egg on its face, and Castro now officially announces that he's adopting Marxism-Leninism, which sets the stage for the Cuban Missile Crisis. In the opinion of this author, Eisenhower's actions in Cuba made the country substantially less safe, and were a step toward the single hottest moment of the Cold War. Perhaps Castro would have always moved toward Marxism, but his specifically requesting that nuclear weapons be moved to Cuba came out of the Bay of Pigs invasion.