Just received mine today. Have not yet had a chance to do any pwning. Upon unboxing, it seems bigger than some of the other comments indicated.
It's very light, but by no means flimsy (*cough* Gyration Air Mouse *cough*). The buttons are light but deliberate, and are 2/3 the length of the device, necessitating a "claw"-style grip. It does seem to glide around rather effortlessly on just about any surface (likely due to the teflon feet). As it lacks the standard FW/BK buttons, it's truly an ambidextrous mouse. The "on-the-fly" switches on the bottom are a nice touch, but I can't see anyone taking the time to flip the switches mid-match. A 1/4" movement @ 1800dpi moves the cursor about half a screen, but the sensitivity is fully adjustable in the software.
Oh, (heh) and all the paper documentation is in Korean with an english PDF on the disc. Unfortunately, the disc only contains a downloader and the PDF, no driver/tweaking software. An internet connection is necessary to install the software and latest driver, but Windows' standard mouse driver seems to work like a champ.
Given its lack of FW/BK buttons and the switches being on the bottom, it's probably best suited to RTS games (hence the Starcraft champ's endorsement). For FPSes, I think I'll stick with my G5, but overall, for a shade over $18 shipped, I'd call this rodent a steal.