My 2¢ on this, I have a QF TK as well as a QF Stealth, which is the same layout as the Rapid.
Personally, I think there's almost no difference. I don't think that the integrated numpad is gimmicky at all, I got used to switching between and it's actually quite useful. However, if you truly almost never use it, go for the Rapid, because it's a little easier to find the arrow keys in fast-paced gameplay or the like.
However, aesthetically the TK has backlighting, which you may like. The Red and Blue have red/blue backlighting, while the brown has white backlighting; it has five brightness settings (2 is usually a good setting), a breathing mode (alternates between bright and dim), and best of all the arrow keys light up when numlock is off and are always off when numlock is on so that you know when you can use it, which I find very nice.
So personally, I would recommend the TK, unless you don't want backlighting and don't use the numpad, then the Rapid is a great choice.
As for keys, it depends on the game you play. I play LoL mostly, and having the tactility of the MX Blue helps me know when I press a switch, I feel more controlled because the click lets me know when I've gotten the activation, and I don't have to press all the way down like with a Red. So with games that have abilities, I suggest blue or even brown, which is a nice intermediate.
But if you play games with lots of double-tapping, blues are not good for that, and I say that as a 130+ typist; double- and triple-tapping are property of MX Red, LLC.
Oh, and as mentioned before, please don't post the same thread multiple times.
