I have the 10" model, zt-280, and it has the same chip/board as the C71, just larger.
the official ICS is kind of bloated, and has alot of the codecs removed. but it is a LOT more stable than 2.3
if you google SjPedro's custom rom you'll find a really nice build. He removed the bloatware, and added some of the codecs back in.
but flash doesn't work. I think there's a way to force it to work on the official build, but not on SjPedro's. but with that said, i still like the custom rom just because it's so much faster. (much better than the GB build)
When you say the "Official ICS" do you mean the one on the Zenithink site? Is that the one that's bloated? By the way, when I play video on my C71, the screen is stretched out. I'm hoping to fix that problem when I go to ICS... but I hear Flash is not working yet on ICS, so I guess I should wait.
So you're saying ICS is faster? Do you mean the touch screen is more responsive? is browsing faster?