I'd keep the 250. I've been on mine for going on 16mths, granted 6 o those were winter and no riding and I had some work to do in regards to this riding with one hand, but...my riding is getting better and better. And not just better from I do things correctly, but better in that my mind, controls and bike are in tune with each other.
Ok, flip side, I still flub the controls. Today for instance, at a stoplight, I put the bike in N, pulled up my visor and started to relax. Well, the light turned green quicker than I expected and in my haste to get my visor back down and my hand back on the controls, I seriously goosed the throttle as I kicked into first. Now, I was on the clutch and aware of what I did, so no harm done, just a louder than normal take off. BUT, I am saying that even with some riding time and "knowing" how to ride, there's still mistakes that will be made. The longer you're on the bike, the more you'll get fine tuned with it. In that time, not only do you know that particular bike better, but you can also hone skills because you are so familiar with it you can adjust. I think those are gains you can't overlook and they will stay with you as you progress to different bikes.
Of course, I'm also a freak in that I normally develop a relationship and get very attached to the vehicles and things I own
