Something to consider when looking at running costs is the cruise speed of the machine.
I own a 500, 206 and 300.
500 cruises at 130kt ( 140 if you are going for it )
206 105kt
300 80kt
Compare distance v hours and the 500 suddenly becomes a " cheap" machine as it uses 20% less component time and fuel to do the same job as a 206. If you are hour counting forget this argument. Plus the 500 is cheaper to buy. Compare to an R44 the 500 compares quite well, both 4 seat machines ( can get 5 in a 500 but a bit tight unless you take some nice stuff in the front). R44 expensive on fuel !
300 is a very good machine but no where to put any luggage unless strapped in the third pax position. It is really a training helicopter and a very good one.
Most important thing if you are buying is to get it surveyed by an independent engineer, it could save you thousands. Drop me an e mail and I will recommend.
Yes I am a 500 fan.