Dude the GAN 460 sucks. I have it and the GuanSu ($8) is literally better.
For the WuQue M, Aosu GTS2M, Valk 4M, and the AoSu WRM
The sizes are all different but the performance is all similar.
WuQue : 62mm
GTS2M : 61mm
Valk : 60mm
WRM : 59mm
I have the WRM and WuQue.
I personally prefer the WRM size as finger tricks are easier. Suck as push reverse U / U'.
Also, the E Perm is much easier on the WRM.
I would personally recommend the WRM. Also, that is the cube that all of the Pros use.