Wendy01

In my experience, Schweser is fine for Levels I and II. I never opened a single CFAI book for those two levels. I do, however, have many years of buy-side experience.

Wendy01

I used only Schweser for bot hlevels, but it feels like level II requires more than Schweser, e.g. the official CFA mock revealed many areas that were missing in Schweser. Such topics as ethics, economics and as it turned out derivatives were not properly covered in Schweser
Qbank was amazing for level I, but not that valuable for level II, at least in my opinion, mostly due to the  question format in Qbank.
For level III I am going to make notes from the original curriculum and practice with questions from Schweser.