I may be guilty of some bias against Mizuno's drivers, but a few swings with the MP-630 Fast Track have convinced me otherwise. It didn't take long before I started referring to this thing as "my little cannon" and I've never had a better year driving the golf ball.
Though the clubface appears smaller than many other drivers (it probably is smaller), I never had trouble missing the clubface enough that I questioned the driver's forgiveness. If you find yourself hitting the very edges of drivers with larger clubfaces than this, you'll want to avoid this driver as you might literally top a few off the toe or heel. On the other hand, if you regularly hit the ball within a full inch of your driver's sweet spot, the clubface area on the MP-630 is nothing to worry about: it's more than large enough for all but the worst types of swings.
I tested the MP-630 with the stock shaft in an X flex and a driver head with 10.5° loft. Previous drivers were all heavier shafts (70 grams or so), stiff flex, and 9.5 degrees of loft. The club suits me and the combination of more loft with a stiffer shaft lets me feel that I can really attack the golf ball when I need to.
The first thing I noticed when hitting the MP-630 was the sound it makes. It's been a long time since I've swatted balata with persimmon, but the noise harkens back to that. In modern day equivalents, it sounds like the perfect combination of a carbon composite material and a titanium or even steel head. The sound is a bright yet heavy "thump" that sounds more like an MLB player swatting a home run than the loud, tinny, hollow noises commonly made by drivers these days. I'm having a hard time thinking of a driver that sounded better, and may very well have to go back to balata and persimmon to start building that list!
The ball flight with this driver is incredibly consistent across the face. I was not punished severely for missing high or low, towards the toe or heel. The driver seems to have a fair amount of bulge and roll, which likely helps here. Distance on mis-hits was perhaps a bit more than you'd see on a super-MOI type driver, but distance loss was less than with some other "player's drivers" I've hit, too. I play a push draw primarily, and shots hit on the toe would simply push more and draw a bit more and shots hit on the heel would start straighter and draw less. Likewise for shots hit high or low on the face - very little would change about the height of the ball.
Distance? The MP-630 is no longer than any other driver out there these days, but it's no shorter either. Driver technology has pretty much maxed out distance across the world of golf, so the best you can do is get fit and try to get to your ideal launch conditions to maximize distance. The MP-630's Fast Track system will help you to do just that.
And how much, specifically, can the Fast Track system do? 45 positions sounds like a lot, and it is. It's too many to discuss, so I'll talk about the extremes and averages: adjustable weight all the way towards the face, weight all the way towards the back of the club, and weight neutral or weight all in the heel, balanced, or all towards the toe.
I play about as neutral a position as you can get: weights are in the 3 and 8 positions - right in the middle both front-to-back and heel-to-toe. I typically carry the ball about 265 to 270 yards with a draw that starts 10 yards right of the target and curves back.
With the weights positioned in the 1/10 positions as far forwards towards the face as possible, the ball flight was noticeably lower and had several hundred less RPM. If I played regularly on firm fairways or in windy conditions I might be tempted to push the weights there - or if I'd gotten a stiff shaft instead of the X flex I have. Trajectory and spin was likewise affected with the weight back in the 5/6 positions.
The heel/toe positions affected things a similar amount. My 10-yard draw turned into perhaps a 13-yard draw with the weight all in the heel and a 7-yard draw with the weight in the toe. Others will undoubtedly be affected more here - I think that a driver's side-to-side weight distribution has less effect on balls hit pretty squarely.
Do I have any complaints? No, not really. After my initial concerns about the appearance of the size of the clubface were allayed by the results, I came to enjoy, appreciate, or like everything about this driver. It looks great, it sounds great, it allows for exactly enough adjustability (without requiring special tools - the wrench Mizuno gives you is just a hex wrench), it's as forgiving as I need and provides the carry distance and ball flight I like to see from the tee.
The MP-630 Fast Track driver is an all-around winner.