I have both a standard BAD-ASS and the Noveske STS.

The BAD levers are much more comfortable - the Magpul levers feel sharp somehow, but I can't find any sharp edges. I don't really know what's going on. The BAD-ASS is also much easier to install, but seems more likely to unscrew itself due to the positioning of the screws. Locktite should fix that problem and I've never seen a BAD-ASS unscrew itself.

Basically, here's how I break it down:

BAD
+ Feel (smoother, yet also more aggressive texturing)
+ Metal vs plastic (arguably stronger because metal will deform/bend before breaking, which is good in a part with low tolerances like a lever, but bad in a part with higher tolerances like, say, magazine feed lips... but I don't know how you'd impart enough force on a safety lever to deform/bend/break it)
+ Ease of installation (doesn't require less-common tools, it's really idiot-proof)
+ Variety of levers to choose from

Noveske/Magpul
+ Cost (half or less of the price of a BAD short throw, should come free on Noveske lowers now)
+ Plastic vs Metal (less likely to get super hot when not wearing gloves)
+ Impossible to remove

I'd say if you have the money, go for the BAD. If you don't do anything besides shoot bench rest and need an ambi or left-handed safety, go with the Noveske/Magpul.