Hmmmm...I think you and I the same person...I'm 50, live in Wisconsin, am a 'recreational' rider, and I did exactly what you're contemplating -- just last week. I switched from a 53/39 double (Shimano 105) to a 50/34 FSA Gossamer compact (with their MegaExo external bottom bracket) on my Gunnar. I run a 12-25 cassette,a and I've ridden about 150 miles with the new setup. It sounds like I ride a little more aggressively than you do. I average about 17-18mph for a solo ride of up to 40 miles, riding in the lower 20's on flats. Group rides are much faster. My initial impressions with the compact crank are:

- The shifting is fine (I lowered the 105 derailleur a bit and adjusted the cable.)
- I'm glad to have the lower gearing on really steep hills, but I find don't use the biggest cogs on 'regular' hills unless I'm really tired.
- I seem to need to move between the chainrings more frequently than when I had the 53/39. I'm not sure why yet...maybe it's the terrain I've ridden, or or my riding style. Or maybe it's because it's been so windy this week I've needed to change gearing as my route heads into or out of the wind. I'll need more miles to figure that out.
- It does give me more confidence that I will be able to deal with whatever is up the road.

The compact seems to give me about the same top and bottom gearing as my other bike which has a 53/39 crank and a 13-29 cassette (Campy). I began to realize last season that I was choosing to ride the Campy bike for most of my long rides, but now I feel that I can deal with whatever comes up around here on either bike. Since I rarely ride in 53/12, except for big downhills, I don't miss anything about the top end gearing. So far, I like the compact. I'm not sure I'm ready for mountains or the Horribly Hilly Hundred, but having lower gears that I can spin does help keep me fresh longer. I don't really see a downside to it.