Also cut the atmospheric effects but made the gates between aread during missions two-way and added the ability to repair your MS by standing near your support ship instead of just healing you a little between each map.
GAS: Added SEED and 00s1 MS, added a full chapter for F91, more suits from Victory, but removed several pilots (mostly characters from other video games, only a few anime characters got cut). Nice atmospheric effects like fog, rain, sandstorms, etc and a few cylindrical battlefields (colony exteriors) you can run all the way around. Every pilot you've never heard of from every game is in this, as is every MS ever from 0079 to CCA and iirc most of the MS from F91 and several from Victory. Other factions' MS can be unlocked but not missions. GBU: Create a pilot and go through the Universal Century timeline, deciding at the beginning of each era which side you'll fight in.
Personally I prefer the latter so I'll just give a rundown of the GBU/GAS differences (Gundam Seed Battle Destiny is a Vita game anyway). The two game franchises may have similar controls but play very differently. GBU/GAS/GSBD is more of a flight sim/shooter type that skimps on meelee to focus on firepower. Vs is more arcade style that limits artillery combat in favor of meelee suits. Battle Universe, Assault Survive, and Battle Destiny are a separate series from Vs and G Gen.