I've been using spacemacs for nearly 2 years now and autocomplete has mostly always worked right out of the box after installing the corresponding layer. I rarely even need to reboot Emacs.

I'm reading this on Spacemacs right now! It's excellent - it removes a lot of the initial configuration investment required to be productive, while letting you customize as deeply as you want if that's necessary. Plus, it has vim keybindings out of the box ;)

Just curious... Does spacemacs only offer Vim keybindings, or does it support Vim macros as well?

Evil mode itself allows for keyboard macros. I do believe there are ex-mode things that won't work but most users never even touch this stuff (i.e. if you press Q in vi/vim).

Spacemacs by extension integrates evil mode entirely, so keyboard macros are available.