I bought the OnTarget2. I had previously used the "charts" to pick my arrow spine the first year. Beman MFX 340's. When I shot, the difference between my broadheads and field tips were too far off despite tuning and I also wanted to use a heavier broadhead, so I picked a stiffer spine and was able to tighten up the broadhead and field tip distance even with the 125 grain broadheads (more front of center). Played around with OnTarget2 and it essentially predicted the 300's were more appropriate with the broadheads I wanted to use. Just happened to get lucky with the arrow length. (was using 28.5 inch and it predicted 28.13 inches). The program predicted I would do better with a weaker spine for my target arrows and this tightened up the groups a little too, but still not hitting the same spot.
In other words, the program will pay for itself (1 dozen 340's wasted)...though you can get the right spine with the trial version. But the full version has some nice simulations. Best one for me is the targeting. If you have a target at 85 yards and you use your 80 yard pin, you put the "pin" on the target your arrow will drop say...10 inches (and it shows you on a target or animal silhouette where your arrow would hit). I "practice" my shots before I get to the range. And my arms don't hardly get tired at all. At the various distance I've gotten good at estimating how high I need to hold to get in the center ring. This has translated into more "kill" shots on the range.
