CJ,
You referring to sport bikes or cruisers? I wouldn't touch anything over a 750 sport bike right now though I'm tempted to add an Aprilla to my stable and I've been riding for about three years now. Everything I've ridden has been a cruiser with the exception of my enduro (650), weight difference in all of them was very little, once you get over 500lbs you can either handle the bike or you can't
And you're right about 250's, some of them are very powerful and very fast, heck my Suzuki RM250 dirt bike was the fastest bike I ever rode, big mistake buying a race prepped bike for my first biking experience, let's just say I hope I got all my crashes outta the way off road with that bad boy
Ride on and keep the rubber side down