450 size - too small for guys over 50 ? :-)
I've had about 20 flights or so on my blade 450 and had my first mishap - a rotor spill into the grass, costing me some broken blade grips and about 3 hours of internet research figuring out how to reassemble the blade grips with 12 parts, consisting of different size washers and bearings for each grip. Man, whas an exercise in finding the right combination of reading glasses and light sources :-)..
Don't know about you guys out there, but when I build my first one from scratch, I am thinking 600+ size.