Cube U21GT (4.1) vs PiPo U1 Pro (vs Ainol Novo 7 Fire)

[UnknownVT]

Hi I'm new to tablets but have owned an Android phone for some time -
I am looking for some advice on 7" Android tablets with 1280x800 IPS screen

On my short list for now are:

Cube U21GT (4.1) 16GB -
Rockchip RK3066, 1.6GHz, Cortex A9 dual core; GPU: Mali 400 MP4 4 cores - NO Bluetooth.

PiPo U1 Pro 16GB -
Rockchip 3066 Cortex A9,1.6GHz,Dual-core CPU+Quad-core GPU Mali 400 MP4 - Bluetooth 2.1

I am also considering - because of the reputation of the AML8726-M6 compatibility with XBMC -
Ainol Novo 7 Fire 16GB (even though it is still Android 4.0.4 - can it be upgraded to 4.1?)
Dual Core AMLogic AML8726-M6 1.5GHz + GPU: Dual Core Mali 400*2 3D - Bluetooth 2.1

There other new offerings using quad-core processors but I had been advised to avoid models using the GC1000 GPU
ref: starting with Post #4 of Ainol's Quad Core ERA..
and this article

Thanks for any help,

Vincent