The 915's are left-over stock on display racks. After getting fit for a 917 matching loft, shaft, and settings to my swing, I see the 917 as being a multi-year purchase. My combination is not available at any retailer. Not exotic, but not off the rack. For me, the 917 was a much better purchase because it is so much better than my 913. The savings by buying old stock isn't much if you amortize the cost over 4 years.

I can only speak for myself. I did not hit the 915 well but loved my 913 D3 until the 917 D3 came out. Absolutely love it. For me the stock 74 pro Fujikura shaft is so easy to load and just hits fairways all day long. I think you will welcome the change. All neutral settings for me. Just took it off the rack and hit it straight 280 max.

I have both and the technology has improved a lot. If you can go to a Titleist Thursday and get a free fitting, I would go and get the right set up and buy the 917D2. Tighter and longer. I picked up 11 yards and my backspin is down to 2300 rpms with a newer shaft.

I had the 915D3, upgraded to the 917D3. I really like the feel, it was worth it. My accuracy has improved and I find my misses are still quite good. Also, I like the shaft options and ability to adjust it.

I cannot speak as to upgrading from a previous Titleist model as I switched from a Taylor Made to the 917D2 and definitely say it was worth it. Picked up 10-15 yards and greatly improved on the accuracy.