If you could get either one which would it be? My son is small so he will fit both till 4 rfing so that’s not an issue. I like the leg room with the radian but hate tightening the straps on it. I haven’t played with the size4me so I don’t know how I would like it but the leg room seems to be the same as his advocate which I hate trying to have to squeeze him in. I can't decide which one to get.