Thanks for the post. 

Handicap should not be a determining factor in which hybrid you select. Think about what your game needs. The HD is designed with more offset and is ideal for the individual who is more steep on the ball. The design promotes more of a penetrating ball flight. The 915H is designed more for a golfer who sweeps the ball and is looking for a little higher flight with slightly more spin. 

I suggest trying both and seeing which one fits your game best. 

Bubba

I will add on to Bubba's spot on comments as usual!

I went to Titleist TPI for a fitting a couple months ago and being a low handicap player I naturally thought I would fit into the 915Hd since I had them in the 913 line.  However, due to my spin and playing factors the fitter determined I should be in the H line! A great example of what Bubba was referring to.

Good Luck!

I too went to an on course fitting and hit both heads.  WOW what a difference in performance.  I am a sweeper and the Hd did not performance well for me at all.  Everything low and right and had no idea where it was going.  Changed heads to the H and WOW, straight at target with nice high flight and a soft right to left draw.  Ended up lowering the loft to a 17.25 and getting the Aldila Black Rogue 85 Stiff shaft with a Golfpride Multipound Midsize grip.....power to burn.....never purchase a club without a fitting....Bubba is da man.....

Go find a TItleist Advanced Fitting Centre and get fit correctly the first time. I use to buy clubs of the shelf, until I had my first fitting and found out just how "incorrect" they were for me. I will never buy another club, without getting fit and its a 3 hour drive for me to the closest AFC.