I know this thread is a little dated, but I had the same question 2 months ago and have since spent a month gaming on a QFR Red, QFR Brown, and HHKB. It really is a matter of taste, but here is a little more detail that may help others. Note that most of my gaming time was spent in Guild Wars 2 which I think is a very good game for testing different keyboards since MMOs require the use of many keys and key combinations compared to other games. Here are some things that helped me decide which board to stick with:
1) Tactile feedback: YMMV but what I've found is that tactile feedback is useful for typing but isn't very helpful for gaming. In fact, the mid-press bump I get from the MX Browns actually confuses me a little when I'm double tapping. For this reason I particularly liked the MX Red and Topre Switches.
2) Force/linearity: I know the MX Red and HHKB are both rated at 45g of weight, but the Topre has higher initial resistance. This can either be an advantage or a disadvantage depending on whether you're more worried about fatigue or accidental mis-presses. Because the MX Reds are so light, sometimes I accidentally pressed a button when my wrist was in a resting position and my hand was on the keyboard. However, this was never a problem when I was actively pressing keys, as my wrists would naturally rise.
3) Layout: This is really only relevant to the HHKB as the RealForce has a more or less traditional layout. Because the HHKB doesn't have function keys, I remapped my GW2 keys from F1-4 to Ctrl1-4. I actually found this to be a superior setup once I got used to it, especially with the placement of the Ctrl key on the HHKB (where the traditional Caps Lock is). So superior, in fact, that I remapped my Caps Lock key system-wide so I could use Ctrl+# instead of F# even when using the QFRs. Not having to reposition your hand after hitting a function key is something you can only appreciate once you don't have to do it any more.
Right now I'm leaning towards the QFR Red as my primary board with the caveat that I've remapped several keys to match the HHKB (tilde = ESC, caps = CTRL, backslash and backspace are swapped). It comes down to MX Red being the easiest to press which is pretty crucial for gaming. Nevertheless, the HHKB is more than adequate for gaming and its superiority for typing may yet grant it the title of being my primary board. We'll see.
