Calumet - 1:07 am on Mar 24, 2013 (gmt 0)
WordPress has a very mature developer community, and you can get tons of off the shelf plugins. I don't think there is really much of a decision here. I use it in conjunction with the membermouse plugin to run one of my sites that brings in over seven figures a year. WordPress has made a lot of progress over the last year or two with speed, and I think it's only getting better.