Today I'm changing the libraries I use from ActionBarSherlock to GreenDroid.
Why? Because the GreenDroid Library has a lot more customization options(and easier).
And beside that, GreenDroid adds more then just the ActionBar.
However it does require some rewriting of code, but when that's done it's pretty easy to create newer layouts, for example the YouTube Layout (I decided which UI to use, but couldn't do that with ActionBarSherlock).
If you're interested, look them up on Google (:
Both libraries also have demo apps in the Market (Or Google Play, but I hat that name).
Samsung Galaxy Apollo (Galaxy 3)(Sold) | Archos 43 IT (Using as GPS unit in car) | Sony Xperia Pro (MK16i) (Sold)
Nexus 7 (2012): (Dev-Tab) Stock 4.3 with Unify Addons
Oppo Find 5: ColorOS (Stock) 4.2.2 with Unify Addons
Nexus 7 (2013): Stock 4.3 with Unify Addons