Pros: Great build quality, price
Cons: Standard keycaps get sticky after a while
This is how it raised the bar; quality mechanical keyboard for under $100? This was unheard of before CM. Pretty much every peripheral lineup of theirs raised the bar; their mice certainly did, especially when you factored in their prices. Ever since their gaming mouse lineup, most other manufacturers dropped their prices to compete. Their Sirus headset is one of few true surround headsets; as in it isn't software emulation, and it now has an amazing price, not to mention it actually has decent bass in addition to good sound quality. This trio is a very rare thing. So yeah, the QuickFire Rapid fits right in with those.
It's a tenkeyless board, which I find ideal for gamers. I never really used my numberpad, and I heavily prefer more mouse room for larger strokes. It takes some getting used to I suppose, but I know I'll never go back.
You can get this board with Cherry MX Red, Blue, Brown, or Black switches. The Red model looks different, as seen in the picture. This is one of the most preferred "gaming switches", along with blacks, since they aren't tactile. Tactile is just unnecessary for gaming, and some might find it to be intrusive. Read OCN's brilliant mechanical keyboard guide if you haven't.
Personally, I prefer Reds for gaming (I haven't tried blacks), and Blues for typing. Browns are just not tactile enough for me, they might as well be linear. Seriously, Clears need to replace those on the mainstream market. Heck, I really want to try Greens too. Blues are almost too soft for me.
This costs almost the same as the QuickFire TK, which I reviewed here. That one has a backlight and more functionality, but the board quality is much worse since it's some China OEM. The keycaps are much nicer, but you can just get a replacement set for the Rapid. It's a compromise really. My full review of the Rapid can be found here.
Having owned both, if I could only choose one, it would probably be the Rapid. But I took the better route; sold both and saved up for a Ducky Shine II, which has a backlight with much more customization than the QuickFire TK, has quality at least on par with the Rapid, with keycaps that feel the same as the TK. Win-win. But now there's a mouthwatering Ducky Shine III on the way...