TiAm frustrating indeed, some people do not get that coexistence of styles exists (for exemple, 3D modeled graphics in game exists, but 2D is still here for a long time, same for animation), and would prefer one thing only to exist for simplicity sake I would guess, quality is never defined by the style itself (or tool in the large picture, as long as they are working) you have chosen, but by the use you make of it (with respects of specifications for the non artistic domains).
I saw triplets of belleville when I was younger, I remember not really understanding what happened but the animation was good.
However, for the thief and the cobbler it seems that there are multiple versions and I did not heard only good things about all of them, qo I do not know which one I should watch (and how to, as I would guess aquiring some of those version would be kinda hard.)
Also, I should rewatch snow white, as I think it was the first "long metrage" movie with color and voices (I remember the old tape, there was a making off I think after the movie, was too young to really bother at the tile I saw it)