I just love Chesnaught so much, it's tough looking yet gentle natured, has a brilliant design and a great typing. In many ways he's the spiritual successor to Samurott in being an helmet-wearing, armoured medieval warrior mammal (with a fluffy face!) that makes a sharp departure from the earlier stages in its line, which is probably why I liked him so much from the get go. Oh and did I mention this thing is really fucking adorable?
Greninja has grown on me a lot since it was first revealed, and I absolutely love its battle animations. It's great that we finally have a fast Water starter, and Protean looks like it'd be a lot of fun to use. My only criticism is that the tongue scarf, while creative, is one of those things that only makes sense as a design choice. Maybe the anime can shed some light on that, it just looks really...impractical, especially in battle.
I'm still trying to get used to Delphox. It actually does look much better in the official art, but the game model just looks so weird and stilted, and falls straight into the uncanny valley. The last thing I wanted Fennekin to turn into was some anthro, but maybe my opinion will change once I've used one.