MO GBA is very hit and miss, even moreso than the console version. But for the longest time I settled for it when it was the only option I had available, and for what it was I enjoyed it. Again, the biggest problem I had was that which I had with MO in general: too much back and forth and so many steps just for a simple task... but in spite of that, I like it. I may be a bit weird for that but yes I own MO GBA and like it. ^^
Oddworld Adventures I & II on the other hand... ah, absolutely awesome too. Definitely good fun has been had with my copies of those handheld versions.
In fact, when my AE LP is done, OA2 won't be too far off.