As a special teams coordinator for my HS team, I love the onside kick philosophy and have tried to convince our coaches to employ it. We have a great defense so I haven't been successful in convincing the HC to do it EVERY time, but we do it about 25% of the time. I'd estimate our success rate is about 25-33%, but it would be higher if we committed to do it all of the time. Every time the other team returns it beyond their own 40 (we kick from our 40), I hate that we didn't try an onside kick.
As far as not punting...I'm not as convinced. I faked a punt from our own 5 about 4 weeks ago, like a week or so after Charlie Weis did it at Kansas (which was really dumb given the circumstances of that game). We didn't convert but our defense stopped them. I felt terrible at the time. I don't regret the decision because it was late in the game, our offense wasn't moving the ball and we needed a spark, but I couldn't imagine doing that in the 1st quarter.
My conclusion is...in youth football, onside kick every time and no punting is great. In high school football, onside kick every time is great, but not so sure about never punting. In college, neither strategy should be implemented. Field position is much more important at the college level and onside kick every time/never punting would put the HC on the fast track to getting fired and never hired again.
