I bought a Thrive (or AT100 as it is referred to here in Australia). I moved away from ASUS for the first time in a decade to go with the Toshiba product (lured by the HDMI and SD slot).
Initially the decision was an epic fail due to the "sleep of death" and random reboot issues. Toshiba's poorly coordinated customer service relating to this problem was probably the worst part of all. I got everything from complete denial of the problem to acknowledgment of the issue and a fix is in progress depending on which customer support person you spoke to at the time. I had the unit replaced but the replacement had the same problems. Eventually they released a patch and upgrade to android 3.1 and then very quickly to 3.2. Since then I haven't had any issues.
The unit is bulkier and feels cheap and plasticky but it is quite durable. It has been dropped many times, flung across the room and thrown down the hallway by my two year old and barely has a mark on it. If the rear casing cracks I can buy cheap replacements in different colours and the replacment battery is really handy for long trips.
Having said all that, I wish I had bought the ASUS transformer. The keyboard/extended battery is worth sacrificing the full size ports IMHO.
On a side note: I just wish I could get the equivalent of an ASUS Transformer that runs Linux, or can be made to run linux. The only option that I can see at the moment is to buy an ultrabook and load Linux on it, but then I wouldn't be able to detach the screen. Plus it would be at least twice the price.