Great ad-block addon! A tad more lightweight than ABP. Currently using µB and ABP (changing between them on different comps), and this is very much a worthy contender!
The only thing I've got to "complain" about is that the different trackers and such are very poorly explained in µBlock (via the status bar icon). +, ++, red, yellow, green square. It is not readily clear what they mean, and what changes will occur if you make one of them green, yellow or red. There ought to be a hover-text for this, or at least a -very available- page in the options which explains this straight forwards.