Q-factor is a fad? Not so sure. There's an entire page dedicated to it in my old Bridgestone catalog (circa 1991). So if anything, it's decidedly not a fad as fads tend to go away.
More specifically, Q-factor may or may not be important, depending on your height. For smaller riders (I'm 5'7"), a narrow Q-factor can give you a more natural stance on your bike. It's becoming more of an issue now (hence why it appears to be a fad) because of the natural backlash against external BB cranks, which are probably more of a "fad" than Q-factor.
As far as which crank to go with, if Q-factor is not a, well, factor, I've found XTR to be the most solid performing crank of the many I've tried. Most recently, I've been on FSA K-Force Light, XTRs, and I'm now running the KCNC triple. I went with KCNC because they were comparable in weight to XTRs (a little lighter, I think), they have a narrow Q-factor and they were competitively priced. I'm somewhat happy with them although my main issues with them are as follows.
They are an absolute b**** to install. You have to lube every last inch of those M-Fers or you will never get the spacing right of the BB cups. I'm pretty handy on wrenching, and I had to reinstall them, no joke, 15 times to get them right, trying various combinations of spacers. I was on the phone with the distributor no less than 4 times before I finally got them on right. Second, they are so minimally shaped that my ankle bangs the drive side arm enough that it causes a pretty deep bruise. I might be able to fix that by switching the spacers yet again, but at this point, there's no way I'm taking those off unless they don't spin anymore. Finally, they chainrings flex under heavy torque.
My K-Force cranks were garbage and if you're worried about banging up carbon cranks, you should be. Mine were in tatters when I finally sent them back to FSA because the crank bolt wouldn't stay torqued. They, of course, did nothing.
XTR is the best crank for the money but I feel like I'm a rodeo cowboy when I ride them. I still have them on my "beater" bike and I never have any other problems. Also, they spin great, just as good as my FSA's w/ceramic BB did. I feel the best option is a BB30 but it will be a couple of years before that platform becomes more widespread. Or the next "fad" as the case may be.
