The Xoom is brilliant. I hate these threads where you only get the negatives.
First the OS. In the UK the Xoom currently runs 3.2 and it does it extremely well. ICS is promised and should be here within a few months, but from people I have spoken to, it really is a lot of cosmetic work, like a lot of these updates.
My Xoom is fast, I've had it for about 6 months now and I have had no problems with it. My son has an iPad2 and had to admit he couldn't find a difference between the two, certainly with regard to speed etc. There is a tiny weight difference, the Xoom is the heavier but in his opinion, negligible. And of course, the Xoom runs Flash.
The Xoom comes with 32gb internal memory and accepts up to 32gb SD card. The iPad has no such facility. It also sports USB and an HDMI which means that it's great for boring the relatives by showing off those photos. But it also means movies etc. can be saved to the device for streaming later if your TV is not an internet ready version.
I'm not sure where the idea that it is a Nexus comes from. To my knowledge it is not!
All in all I would say it's a good buy but it's all down to choice. If you want a second hand tablet at that price, well we pay our money and take our choice. I'm not sure I would like a second hand tablet but that is just my feeling.