uBlock is a general-purpose blocker — not an ad blocker specifically.
uBlock blocks ads through its support of the Adblock Plus filter syntax. uBlock extends the syntax and is designed to work with custom rules and filters.
On average, uBlock really does make your browser run leaner. 
uBlock on Github
Its open source mentality, the speed and memory consumption, ... I've had nothing but good experiences from uBlock.
My browser feels snappy again.
Remove Adblock Plus and install uBlock, you won't regret it.
Update 10/5/2015: uBlock has been renamed to uBlock Origin
In a Reddit post, the reasoning behind the move from uBlock to uBlock Origin is further explained.
The plugin was originally created by gorhill and got help from chrismatic. It seems both had mixed intentions for the project, resulting in the rename.
-- gorhill got tired of dozens of "my facebook isnt working plz help" issues.
-- he handed the repository to chrismatic while maintaining control of the extension in the Chrome webstore (by forking chrismatic's version back to himself).
-- chrismatic promptly added donate buttons and a "made with love by Chris" note.
-- gorhill took exception to this and asked chrismatic to change the name so people didn't confuse uBlock (the original, now called uBlock Origin) and uBlock (chrismatic's version)
-- Google took down gorhill's extension. Apparently this was because of the naming issue (since technically chrismatic has control of the repo).
-- gorhill renamed and rebranded his version of ublock to uBlock Origin.
So the original uBlock extension got handed over to uBlock Origin. Time to update your plugin!
Save yourself memory, CPU and get a smoother web browsing experience in return. Get uBlock Origin.