[quote=edborg]I am interested in the U1 as well.
It's double core, IPS, good RAM, thin, nice and has a form factor that I like (4:3).
It also has all the ports that I need, microSD and mini USB (also OTG?), unlike the Nexus7!
If battery is a weak point, are there other RK3066 candidates with a better one?
Apparently there's no rooting for JB yet, but I have read that rooting should be possible with a chinese tool called ShuameSetup_0.8.9_general.zip and/or a russian one called pipom1_JB_root_by_krava33.rar (to be found by googling). However, I am not endorsing those, as I know nothing about them yet.
What about CWM or other custom Recovery system that allows NANDROID backup?
Note: the russian tool uses a program that is also mentioned here: http://www.flashmyandroid.com/forum/showthread.php?1773-pipo-m1-max-how-to-root&p=12150&viewfull=1#post12150
I expect that there will be quite a bit of development for the Pipo M1 and wouldn't be surprised to see a CWM version before long. I am not so sure about the U1.
I find most people are interested in the larger devices, as the prices are very reasonable. 7" RK3066 devices are still relatively expensive when compared with the 9.7" and 10.1" devices. Personally, I only recommend 7" devices for people who plan to do a lot of reading, or for children.
Hopefully the battery sizes will get larger and the prices will get smaller.
There are new 7" RK3066 devices being released every day. I will be on the lookout for one that has the correct balance of performance/features and price.