Plenty of features; working for me in FF 30.0 Rated 5 out of 5 stars
This add-on has been working for me consistently, so perhaps the issue WileyM was having with Firefox 29.0.1 was isolated (or I somehow missed a break in functionality before I updated Firefox)?
The ability to sort, check, set, edit, and block cookies makes this add-on above-and-beyond. Other add-ons, such as Biscuit and Quick&Clean, are not nearly as fine-toothed and as precise.
In particular, I enjoy the ability to spot cookies I've noticed tend to "hide" with different but equivalent names: http://example.com, http://www.example.com, and http://subdomain.example.com can all be sorted now to review them all "per site" than strictly alphabetically (Cookie Manager+ --> Tools --> Options).
Anyway, excellent add-on. A bit advanced, so possibly overwhelming for 1st-time privacy fanatics, but equipped well for powerusers familiar with cookies.