First and foremost, I'm a roadie. When I first got on a mountain bike, I went clipless almost immediately, thinking that I've been using clipless on the road for years, it will be no problem. I was wrong. I took a HUGE fall on day 1 that was a result of simply not being able to unclip quickly enough on something simple. The result was that I got "gun-shy", scared to attempt more technical features. I'd unclip and walk. After switching to flats, I'm more confident and willing to try bigger and more technical features without fear, progressing my skills at a faster rate than I think I previously would have. I don't really feel that I'm giving up much in terms of pedaling efficiency. I ride with several guys that clip in and on the longest climbs that we hit (granted in NJ, nothing is very long) I certainly more than capable of keeping pace with them. I really do think that good flat pedals and proper flat pedal shoes make a difference here. I'm using Shimano XT flat pedals and Specialized 2FO shoes. The 2FO shoes are WAY better than the Vans I used when I first switched to flats. The Vans sole was way to flexy, so when you're trying to put power down on a climb or trying to get over a feature, you can feel the sole contorting around the pedal. The 2FO shoes are really stiff and at the same time the rubber is really grippy. I have a set of Giro Riddance shoes on the way, I'm anxious to see how they feel.