I don't know much about Android tablets, but my experience with my HTC G1 Android phone underscores a significant concern, namely the question of how much customization of the OS is required for your device, who does this customization, what happens after they go out of business, etc., whether you'll be able to upgrade to new OS releases promptly, with long delays, or not at all.
If I buy a Windows laptop from a reputable vendor, I'm seldom very worried about device support. I expect that the base Windows OS contains device support for nearly all of my hardware, and that vendors provide device drivers for the rest. I expect that I can install the base OS, and then download any additional necessary device drivers, and get everything working.
If I buy an iPhone or iPad, I expect that on the day a new OS release comes out, that it will be available for every model, and that Apple will have tested it against them all.
If I buy an Android tablet ... what happens then? The vendor will provide an initial software revision, but where do upgrades come from? Will I be able to run some "generic" software rev, or will I need to wait until that vendor prepares a release that works on my hardware? Will "flybynight.cn" be keeping up with this? HTC is a fairly large and reputable maker of smart phones, but my G1 is still running a pretty old version of Android because HTC hasn't made an upgrade available, and I can't just download some generic release from Google, because it has to be customized for device support for my model of phone.
-harry