According to Syracuse University Press (The Essentials of Ibadi Islam) the Ibadi movement started up 20 years after the death of the Prophet Muhammad and is seen by most Muslims and historians as a reformed sect of the "Kharjite" movement.

Shia's view on the Ibadi community started when it was still known as the extremist Kharjite movement - Shia-Ibadi relations were bad at that time of early Islamic History.

Today the Shia disagree with some Ibadi practices but overall Shia muslims tend to favor the Ibadi over their sunni counterpart and can be seen from Iran's (biggest Shia Country) side, in where, they maintained good relations since the Islamic Revolution.

The Sunni's also have accounts in early Islamic History that reports bad relations between the two and in general, the disagreement comes off Hadith's - the Ibadi accept far fewer hadith's than the Sunni and those they do accept are usually not accepted by the Sunni's - but going to modern times, many Sunni countries tend to have social, technological and economic ties with the only Ibadi Nation in the world Oman.

It is particle to note that even amongst Sunnis,Shia's and Ibadi there are split groups and factions that may have different opinions than one another but as far as accounts look at it, Sunnis and Shia's both had a bad early history with the Ibadi and overtime they started to have ties (Proven by Iran and several Sunni's country Foreign Relations)

Sources:

Saudi Arabia-Oman Relations - Foreign Ministry

The Essentials of Ibadi Islam - Book, Syracuse University Press

Islamic Modernism, Nationalism, and Fundamentalism - Book, Chicago University Press

Ibadi Islam - Introduction, by Valerie J. Hoffman - University of Illinois

~DaveV6