i have both and without question the oscar is 100x smarter, more personable, active, and enjoyable to watch
my gt is frickin l.i. he attacks the pellets and misses by like an inch, not just that but he does a lot of stupid *****
my dad thinks he has mental retardation... im serious
but my oscar is like a dog.. ive heard a lot of ppl say that but its true... my gt has the personality of an ice cube and the eye-sight of stevie wonder, he bites me when my hand is in the tank (but still backs down to my o)
regardless though, i still love them both
but go with a nice oscar