The problem I have with Spacemacs is that it's almost too fancy.
Even as a moderately experienced Emacs user I found the defaults overwhelming. As an example, it displays lots of incomprehensible to the new user information on the bottom that changes with file type. Compare that with ye olde Emacs starter kit, which just fixed up some basic key bindings and gave it a more modern colour scheme.
> Even as a moderately experienced Emacs user I found the defaults overwhelming.
I agree. There is a lot of "magic" going on, and it doesn't help that Spacemacs is a lot slower and less stable than my less-intensive personal customization.
Of course, that's the problem with any significant starter kit. As a new user, now you don't just have to learn emacs, you have to learn emacs + whatever heavy modifications they've done to emacs.
In principle, I liked Spacemacs, but stability is a big problem. Often certain org functionality stops working, etc. I now have a reasonably stable snapshot and I just don't update ELPA/MELPA packages anymore, because the risk is simply too big that things break (yes, I know that you can rollback).
Another problem that I have been running into is that Mitsuharu Yamamoto's emacs-mac, which is IMO by far the nicest Mac version regularly seems to trigger a bug where WindowServer starts using 100% CPU. I haven't really nailed it down (I only notice it later when the fans start getting loud), except that it only occurs sometimes when I run emacs-mac.
Personally I find that a better starting point.