Every iteration of driver will give you better performance. I have found that as the drivers have progressed from the 910 to 913 to 915 that the playability of the mishits was much better. They were less off-line and the distance improved. For a pure hit, there has not been a lot of distance improvement.

I would wait until this fall and then look at the 917. I looks to be a great driver. I have been playing the C16 (917 prototype) and it is by far the best driver that I have had from Titleist.

If money is an issue, the 915s will come down in price after the 917s are released. The 915s introduced the slot on the metals and have a larger sweet spot that the 913/910s. I'm waiting to look at the 917s since I already have a 913