I hear people say that a trad Catholic need only get missals that are pre-1955, but what makes this missal NOT a trad Catholic missal??? People tell me it is not but never give the details as to why. What exactly is added or taken away that makes this not a traditional Catholic missal?

 http://www.baroniuspress.com/book.php?wid=56&bid=4

I have not gone through that specific missal. But if it is a 1962 then there are certain assumptions that can be made.  Those people that are warning you about any missal after 1955 are wise.  Why? Bugnini began to get his claws deep into the rubrics about that time.  Even though the 1962 is the last authentic latin missal, how much can it be trusted if the architect of the destruction of the church was involved?  

Bugnini didn't bring about the Novus Ordo overnight.  He introduced it slowly.  Therefore, when looking at this issue, look a that the changes that eventually lead to the development of the Novus Ordo.  Some might seem trivial, others overblown, and others good.

Dialogue Mass was re-introduced in 1958. Between 1960 and 62, feasts were eradicated, parts of the Canon were changed, the insertion of St. Joseph's name into the Canon, and the elimination of the 2nd Confiteor.  

For a more in depth examination read Fr. Patrick Perez's article The Missal Crisis of 1962.

Robert