Couple of other points worth considering. As Gene pointed out, vision is one, and at almost 50, I find I either need more magnification, more light, or both. I used to shoot handguns at 50 yards with open sights, now I can't get anything to focus, so no more pistolas :-(. I mostly agree about 10X being the max needed for most AG shooting, that is the middle of the range on both the scopes on my PCP's. Which is important in it's own right, pretty much all scopes are at their best in the middle of their range. I prefer 40-44 mm front lenses, I think it's a good compromise between "light gathering" and weight, especially if shooting at longer range. Also, the larger lenses will stretch your shooting time, my first rifle had a BSA 2-7x32, decent little scope, but switching to a 44 mm added at least an hour to my shooting day. I've tried quite a few scopes over the last few years, and currently have 3. Smallest is a BSA 4x AO, perfect fit for the Gamo 440 it's on, I've basically got that one set up as a 10M indoor shooter. The other two are both on PCP's, the S400 is wearing a Simmons 44 Mag 6.5-20x44 and the Cyclone has a Bushy Legend 5-15x40. Both are mil dots, I just prefer that reticule, both are/were under $200. I think the Simmons is a little sharper, but I wouldn't hesitate to buy another Legend, I think it's a great bang for the buck. Although both are large scopes at around 15" long, they fit their rifles well. That said, I'm trading the S400 off on an S200, so will be looking for a compact scope, that' why I'm looking forward to Gene's review of the Timberline. Later.
Dave