im 5'5, but have really short arms for my height. It sits pretty will, but when I grab the bars I have to position my legs towards the back tire(not a problem while riding, thats just for sitting still) and ya my body lays on the tank while riding, so I pretty much have to ride in a full tuck at all times. Other than that I found it to be pretty nice. I just couldn't handle the super aggressive position for long rides. I haven't got a chance to sit on a CBR600 yet, but I've heard good things. As far as a GSXR 750 goes they sit and ride really comfortably for me (only rode one that was droped and stretched) and have seem to have enough power for me not to outgrow. I like every single thing about my ninja 250, except the power, it would be nice to find something pretty close to it though(don't like the ninja 500s)