Got given one of these at work. I must say that I'm very impressed with it's USB performance even over USB 2. It hands two decent resolution monitors with easy. I do need to update the firmware as the mouse can be a little stuttery at times but apart from that I would totally recommend it.
They are a bit pricey mind, even on eBay as I was looking at one for use at home.
For the time I'll have to stick to a thunderbolt to HMDI (second external monitor) and a cheapo USB3 hub.