Keith, the riding position on the 500 is completely different than the 250. You feel like you're on a sport bike on the 250. The 500 has a very "tall" and upright seating position. It's somewhat contrary to the appearance and design of the bike. It doesn't really feel like a sport bike when you're on it...it almost feels like it's set up for off road action. Don't get me wrong, the bike is very comfortable, it's just the seating position caught me off-guard.
The bike is as comfortable, ride quality wise, as the 250. Probably a bit more so. Tire pressure is much higher on the 500.
The 500 puts out 2X the power. There's a lot more torque down low and there's no real need to rev the bike high unless you choose to. Compared to other bikes out there, 50 bhp may not sound like a lot, but the bike has NO shortage of power. It pulls strong right to the red line. Engine is quiet and smooth - - a real pleasure to ride. Again, there is a significant power difference between the two.
As far as extra weight and size? Not an issue unless you were short. The 500 is essentially as nimble as the 250 in my riding conditions. The 500 never feels heavy.
I've been riding the my 1982 BMW for a long time and have only recently come back to Honda, so my perspective on these machines might be a bit different compared to other folks who are driving different modern bikes all the time. My BMW is "old" compared to these modern Hondas. The two Hondas we have are fantastic machines that I'm really enjoying