Well when it comes to commuting, I know when a bike feels small. I mean it literally feels like I am riding a BMX bike. Now being a clyde, I have found the larger the frame, the more comfortable it is. Of course this could just be my body having shorter legs and and longer upper body. I will admit it is a little tall getting on but I am happy with that. My GF Utopia is a 19 inch and is perfect on some levels...however I sorta wish it was a 21 and came up a little higher. I mean it just seems nicer in terms of feel when I am on the streets. I am comparing it to my European commuter bike. It is a 21 and feels a little bit better but needed to have a 135mm stem to really feel good on it. Where I was wrong was that I thought the mountain bike would be different. But the large frame feels good on the trails as well. It is because of this I do not ever think I will own a road bike.