Put it another way, if I run Raspbian and OpenElec what do I gain by also running Android Kit-Kit ?
I have no doubt Android can run on the Pi but when put against Raspbian and OpenELEC I don't think it really has much to offer apart from novelty value given it's old processor and lack of RAM.
Nevertheless I can see the following possibilities (some of which I maybe wrong about):
-Angry Birds and other limited Android apps that don't require ARMv7.
-Better YouTube player
-No Neflix, Hulu or any other DRM based video service
-Better browser but no Flash Player support due to lack of ARMv7 processor (can use cloud based browsers as alternative to Flash Player i.e. Skyfire and Puffin).
-Skype (although I suspect this may not work properly and would also require external audio capture device)
-No access to Google Play Store (but apps can be side loaded as already mentioned)
-No access to Pi Camera
-No access to GPIO port
-No access to MPEG-2 and VC-1 hardware codecs even if you have purchased license key
-Limited USB hardware support (drivers much be cooked into ROM first you cannot simply install drivers like traditional Linux)
-APKs easy to unpack, tweak and repack to remove undesirable behaviour in applications
-Needs 512MB RAM and thus may not support older 256MB Pi.
If you're serious about Android then buy a ready made HDMI Stick / BoxTV they're cheap and pack a lot more power than the Pi.
Richard S.