This past week I was fortunate enough to go through a very intensive driver fitting (about 3 hours). I tried pretty much every loft and shaft combo that could make sense, and I came away very impressed with the 913 over the 910. The sound difference is the first thing you notice, a very solid sound at impact but not loud like some other manufacturers. The sound really does reinforce the feeling you get when you make a good swing. The club face feels more firm, but not hard; lots of spring in the face without being "mushy". For me the best shaft was the 70X Phenom, but their line-up is certainly top-notch for shaft selection. I did not take my 910 to the fitting so I can not compare numbers, simply feel and I did feel more comfortable and confident swinging the 913. The D3 is a great club, normally amateur players are intimidated with smaller heads or shy away from clubs that claim "workability" but I'd argue the D3 is as forgiving as any driver on the market for maintaining distance on off-center hits. Anybody who upgrades will not be disappointed. Lastly, the looks are second to none. Very elegant look, doesn't resort to gimmicks like some other companies. Pure class all the way (Think Apple, sophisticated style all the way)
*The 913F was great, I cannot wait to pre-order one of those also!