my wife has the Grand Neo.. bigger screen but lower specs among the 3..

the m2 is the newest among the 3, Z30 is the oldest.. but specs wise, Z30 is better with super AMOLED screen, better resolution, 2mp front camera, 16GB internal and 2GB ram, it's only dual core but 1.7Ghz.. i just don't know if the BB OS for its touchscreen phone is better than the Android OS.

I say go with the more expensive among the 3.. hehehe that's what I always do.