Very nice unit.
It's small and neat, barely visible on the desk, weighs only about 350g so is very portable. It takes power from two USB sockets, so no separate power supply required. I've run it on an iMac and even from a tiny netbook using only battery power from the netbook.
Works under Ubuntu linux and Mac OS. I've not tried W7 or older versions of Windows, but Samsung have stated it is W7 compatible.
I even reinstalled Linux to my netbook using only this drive.
I've used this unit to read data CDs/DVDs, and to burn files to DVDs and bluRay disks for backup. I've only used 25Gb disks for writing, but I understand that this unit will read/write up to 128Gb disks (it's BDXL), which will be a real bonus when high-capacity disk prices come down.
A 25Gb disk took around 17-20 minutes, which, though it sounds bad, is about as fast as you can get with any recordable disk media - actually faster than CD or DVD speeds.
I've not used this to play movies - my main need is as a backup device.
No compatibility issues I've seen yet. I tend to buy branded disks anyway, though I don't buy premium disks, but 2 different brands have worked fine.
Very pleased. Neat, fast, good price, good capacity, compatibility and no separate power supply. 5 stars.