The two bikes are as different as two bikes can be and still both be motorcycles, and there are probably just as many riders out there that would prefer the Bandit as there are that would prefer the "M".
I could sit here and tell you all about the bandit and how much better I like it than the M50 I had, but the truth is I really liked the "M" too, I like all motorcycles, right now the Bandit is my favorite for shorter (under 4 hours) rides, for longer rides I still like my Road King better.
If you are a motor head you will love the motor on the Bandit, it pulls from 80 just as hard as the "M" pulls from 10, and it's smoother than the "M".
Why don't you tell me a little about what you expect to gain from changing to a Bandit from the "M", and a little about how long you have been riding and what kind of riding you mostly do
How much higher is the Bandit......do you notice the height vs weight differance?
Do you notice much of a change with the chain drive....extra gear.....overall performance?