Wow, $100 for a freaking keyboard ?.... Does it do more than type a letter when you press a key?
Most (inexpensive) keyboards have small rubber domes under the keys which give off a kind of squishy undefined feel when you push a key. These higher end keyboards have mechanical switches instead of rubber domes, which are a lot better for gaming/typing. You get a better feel and responsiveness, especially for games which require quick or repeated keystrokes. I bought a Corsair mechanical keyboard and would never go back to regular dome keys. Logitech makes solid keyboards so this is actually a pretty good deal.