There are no real differences other than hierarchy integration etc. With the EBS running alongside OFSA you have the option of loading hierarchies and ledger data straight into OFSA which can be a double edged sword from a practical perspective. EBS of course has a larger number of global rollouts as there are many more users of the GL worldwide than OFSA but you cannot really compare the two - apples and oranges..
In terms of differences between OFSA and OFSAA - there are no real differences (i.e. business processes supported) one is just a later version of the other with various enhancements etc. i.e. you can do some more stuff in OFSAA but from a process perspective they deliver the same fundamental measures and functionalities. OFSAA is really more reflective of the Oracle acquisitions of late. More emphasis on technology like Hyperion as opposed to Express, more Reveleus influences in the data model and functionality etc.