One of the most frequent operations I do in source code is to add, remove or toggle comments over blocks of code. I used to use the TComment plugin for Vim to do this.
Recently, I discovered Tim Pope's Commentary plugin that does the same. I have switched to it since its code is smaller and simpler. The only operation I use is to visually mark the lines and
gc to toggle commenting on it.
Tried with: Vim 7.4 and Ubuntu 14.04