I've read other people who've had small issues with both sets, but my experiences with them have been nothing but positive and I usually have bad luck with these things.

I'm not sure if it was mentioned anywhere else (maybe it was shown in a video?) but Flowey has replaceable faces which I was not expecting and am really impressed with. My personal favorite is just the ;p face but I like all the faces they included. There's even a somewhat creepy and somewhat cute Asriel face.

Also really impressed with Undyne in-general, particularly that her spear is removable (which there are a number of good reasons for). Her and Flowey are both really powerful standouts in this set.

I really hope they plan out another set where they cover Asriel, Asgore and some of the other background characters. I'd seriously give almost anything for a vinyl of Asriel that went along with these others.

Here's a full gallery of them in-hand, including all of Flowey's faces:

https://imgur.com/a/m9Ju0