I had one, and I will have to say that not only did my wife hated it, and my then 7 year old daughter (now 9) didn't like to ride on it either and she LOVES to ride. After only a short ride, the squared edges were pushing into their thighs. My wife is rather tall at 5'11", but not a heavy weight at all.. and my daughter, well she was 7.. so, she probably weighed 50 lbs?
Glad to here from R34ME that his does fine with it though, it is a nice looking seat and a great concept.