I'd prefer neither really. Didn't enjoy The Incredibles and Monsters Inc. should really be standalone shouldn't it?
Toy Story, Cars and possibly Ratatouille are the only ones that, in my opinion, have scope for sequels. Perhaps A Bug's Life, but that's so far in the past I don't think the audience would connect (plus, for totally unknown reasons to me, people didn't like it as much(!))
I will await it with as much excitement as every Pixar film (the best film production company in history, imho) but I'll remain my judgement as to how good it is until I've seen it.
Monsters Inc. is my favourite Pixar film.