I've got two of these now, one in my MacBook Pro setup and another attached to my wife's iMac. Mine is plugged into AC as well, hers is not; no problems on either system. Having gone through a number of other hubs, this is a pleasant surprise.
The addition of a sliding tray for the hub is a great idea, but note that the hub in no way locks or clicks in place when it's in it, so you won't be able to mount it vertically (e.g., attaching it with velcro to the side of a desk, etc.) unless you bypass using the tray (which comes with two mounting screws), so not a big deal there. But it's an odd omission.
One complaint: the blue light. I understand the necessity of a "I'm getting power/I'm connected" light on a device, but the blue light on this illuminates very brightly. Usually not an issue but if you have your computer in a bedroom, note that you'll need to shut down your computer (and not just sleep it) in order to have that light go off. (And that blue light seems to be on every device these days, eh.) Just FYI.