It's most likely a motoblur thing for the most part, however the entire thing is cheap, nasty and poorly built.
Mine is rooted, but not running a custom ROM, as I wanted to keep the functionality of the WebTop dock. I was however running LauncherPRO (I had also tried ADW and GoLauncher).
I wouldn't recommend one to anyone.
I'm due an upgrade in two days, no idea what to get though, or what to wait for (if applicable). The Nexus Prime is a proper letdown (plus I really REALLY despise Samsung phones, they simply don't work and feel nasty), the Sensation XE isn't exactly all that, and the myriad of SE devices are foul.
At a loss