I've been golfing with my 909 for a while now and have never had a reason to change. I'm not very long, but I hit about 270 avg. and starting to wonder if I can get some length. Just my opinion, but as much as I like Achusnet, Taylormade has always been the longest driver for me, so I prob should go that way, but TM always looks gimicky even if they are the longest...but the boys at the club are hounding about my 909. Its the feel, crack and accuracy of the Titleist, even back to the 975D. Love it. Who really cares, why not tee up this new 915 and give it a shot at least. I'm due.
I can assure you that 270 is much longer than average. If you want to upgrade for the sake of having something shiney and new though, hell, go for it. You may pick up yards with the newer 913 or 915. Demo it first though, obviously.