-The programmable thumb buttons are the best idea ever. Instead of just using my thumb to jump with the space bar, I can do other things that would normally require me to remove my other fingers from the WASD keys. Being able to quickly go prone by mashing the first button with my thumb has saved my life many times.
-Fully adjustable lighting is very cool
-Braided USB cable
-Very responsive
-You can freely program every key, or turn them off. I immediately disabled Caps-Lock and the Windows key.
Weaknesses:
-Manual is very basic. I have no idea what these (G) and (M) modes do.
-Requires 2 USB ports
-Backlit keys are rather dull in the daytime, but turn off the lights and they really look sweet
-You need to download the driver/customization suite from the razer website, since no disc is included (website worked perfectly though, and no driver issues whatsoever with Win7 64-bit)
Summary:
Feels well-built, looks really slick, and the programmable thumb buttons are heavenly for any kind of gaming. Best keyboard I have ever owned.