Pros: Not the obvious target, more potential for surprise. The beaches have a gradual slope in, which meant landing craft could ride right in to the beaches and their cargo be unloaded. The beaches could support heavy vehicles (tanks, trucks etc). A bit closer to Paris

Cons: Further away from UK coastline which meant a longer sea crossing. Paratroops had to be flown in from further away - more chance of planes going off course etc. The beaches had limited exit points to move inland, if these could not be taken there was a chance of invasion forces being pushed back in to the sea. There was some pretty good armour in the area, like the guns at Pointe Du Hoc. Required the mulberry harbours to be built as there was no way to get large ships in.

There are probably a few points but thats the starters.

The failed Dieppe raid made the Allies realise that they could not capture a ready made port, hence the invention of the mulberry harbour.

The Allies went to considerable effort to disguise the landing area. In the months leading up to D-Day for every bomb dropped on the Normandy area there were three dropped in other areas. They pretty much bombed the entire coastline from Normandy to Pas De Calais.

In addition they had (eventually) recruited Joan Pujol Garcia, otherwise known as agent Garbo to the allies and agent Arabel to the Germans.

Garcia had (falsely) offered himself to the Germans as a spy, claiming to travel to the UK as a Spanish diplomat. In fact, he was a chicken farmer and began fabricating "intelligence". The Germans believed everything he made up. He offered himself to the Allies several times but they ignored him. He was eventually recruited in to MI5 after his reports showed up in enigma traffic that the Allies were decoding. In the run up to D-Day Garcia, under the direction of MI5 repeatedly told the Germans that the invasion would come in the Pas De Calais area, in fact even as the invasion was taking place he was sending reports to the Germans stating that the Normandy attack was simply a diversion tactic designed to mislead the Germans so that they'd move reinforcements down to the Normandy area and then attack in the Pas De Calais area.

At the same time the Allies invented a whole new army, based in south east England, they even appointed Patton and Montgomery as commanders (US 1st Army Group, British 21st Army Group. The armies didn't exist, it was fake. They even had people trudge around soggy fields so that if the Germans did manage some reconnaissance they'd see what they expected - an army camp with signs that it was inhabited. Patton in particular was often photographed visiting troops or embarkation points. Aircraft and boats were scattered around as well to try and make it look plausible.

The whole diversion plan was called Operation Fortitude. There are several books on the subject.