I first saw some eps of GTO years ago when it was on SciFi channel in the UK, when they stoped showing them ( was on friday midnight to 3 or 4 am i think ) i was pissed cuz i saw alot of good anime which included GTO, also ninja scroll, macross, akira and alot more.
I have recently started getting ahold of all the old anime i can remember ( which is hard since it was so long ago lol ) but i remembered this series easy since it was one of the funniets i had seen.
I defenatly recommend it, as for the animimation quality... since i watched the anime on Scifi years ago it doesnt bother me and i think its fine. As for the english dub ..tbh i dont no, i always watch the anime in japanese with english sub, sounds much better.
Im still watching it atm i have never seen the whole series since scifi only showed about 5 eps of any series befor changing ..kinda dumb really but still.
Iv read what u'v all said about the ending and tbh even though i havnt seen it myself yet, that kinda ending is fine to me, the endings i hate is when main characters die or its so confusing your head explodes ( points at Divergence Eve & Misaki Chronicals
)
anyway yea ..great anime