You will find that the soteriology of the Roman Catholic Church and the Eastern Orthodox Church does vary from one another.
The Roman Catholicism has much more in commun with the Protestantism than it has with the Eastern Orthodox Church.
Both the catholics and the protestants understand the salvation in the same way. They have adopted the theory of Anselm of Canterbury who said that Christ died on the cross in order to satisfy God's wrath, or God's honor.
The protestants see death as a punishment from God, they do not see it as a consequence of sin. So, they believe that, because of Adam's sin, God could no longer look upon man and someone had to die in order to make ("cosmical") justice.
The protestants do not understand what Christ did on the cross; they don't understand that Christ took the sin of the world because it is sin that makes us death and separates us from God. They do not understand that Christ came to defeat death and give life by restoring man's comunion with God and by giving the possibility (to man) in moving forward in God's love. They think that God sent his Son to die in order to make justice; they think that Christ "paid" (like in a trial) for our sins.
The catholicism turned christianity into a religion of merits and also terrorised people with Hell. Also, catholics do not have the uncreated energies from God. For them, grace is a created energy (favour/love from God). They believe that God does not comunicate Himself through the sacraments, but they believe that through sacraments, God comunicates His grace. And this grace is given to those that participate to the sacraments and do good works. The God of catholics is a distant God and the Pope is considered to be a vicar of God and that he (the Pope) distributes the grace of God.
The protestants gave up the Sacraments (since they do not give them God Himself) and formed the doctrine of grace (by grace they understand "unmerited favour/love from God"). But they make a separation between grace and God's love because they do not believe that grace falls upon everyone, but only on some elected people. Also, they do not believe that they partake with the body and blood of Christ, they take the Holy Comunion only in a symbolical way. The God of protestants is also a distant God, a God of sermons; the protestants talk about God, sing about God, praise God but they are not
in God, because they do not believe that the Holy Mysteries give you God in a mysterious and real way.
So, the occidental christianity (whether is catholic or (neo)protestant) is very very different from the oriental christianity.
Maybe the only thing that we have in commun is that we believe and confess that Christ is the Saviour of the world, that Christ is both God and man and we believe in the Saint Trinity. But even in these aspects, there are differences and nuances.