I do not have either of these and only hit them a couple of times each at the store. I do have a Titleist 910 D3 Driverand a FT9. Which in my opinion is the same thing with out the adjustments. Both of these felt very solid to me, and sounded really good too.
The Titleist 910 D3 Driver delivers longer distance through a technologically advanced head design with a responsive, fast face insert that creates a ball-speed area that is 10% larger than other drivers. The patented, innovative, SureFit Tour dual-angle hosel provides precise and independent loft and lie adjustments to fine tune ball flight for more accuracy and control. The 910 D3, on the other hand, was designed to promote a lower, boring, more penetrating ball flight, and is said to be more workable. Noticeably absent is the “DComp” model. While the 909DComp used a composite crown to move weight lower and deeper, thus improving the location of the center of gravity.
The titleist d3has a 17% thinner crown allowing more weight to be positioned lower and deeper in the bezel to optimise the centre of gravity and the bevel weights can be adjusted to alter swing weight of the driver. The Titleist 910 series incorporates Variable Face Thickness Technology (VFT) that mirrors the shape of the clubface with a thicker central portion that is equidistant from all points of the face perimeter resulting in an increase in maximum ball speed area and a 15-18% increase in total ball speed.