Never reached being a vim power user. Somehow I always end back up to an IDE especially when it involves a bigger project. Could someone share some power user examples when only using vim it really shines for programming?
The best thing about Vim is that you don't have to choose between Vim and an IDE! Any text editor or IDE that's even moderately popular will probably have a decent Vim plugin. The only downside is that you generally won't have access to Vim plugins (abolish.vim is the one I find myself missing the most: https://github.com/tpope/vim-abolish).
Personally, I learned to use Vim via the VsVim plugin for Visual Studio.