I've had both types of bikes, bent's and DF's but for some reason, my knees didn't like then bent very much, you do have to "SPIN" harder to make a CLWB or LWB bent go up hills, I've got two types of arthrtis and both effect my knees. Now bent's FLY downhill's and my neck doens't care for my hybrid DF's, so sadly I can't be "comfortable" on any style of bike, rats. Still the bent had ONE GREAT quality, I LOVED, being able to just, look straight on with my head in a normal position! On my DF hybrid, even with a 35 degree stem, I'm still looking at the ground or my neck get's stiff!