For commenting and uncommenting I now use the vim-commentary plugin, also the NERD commenter can be used as mentioned in: How to comment out a set of lines which are selected in visual mode?
I would like to know if there is an easy combination to change comments, for example like cic or delete the comments like dac. Note that this does not work (for as far as I could find) with the vim-commentary or NERD commenter plugins.