It is difficult to compare true operating costs between a 206 and a D or E model 500 unless they are both brand new or your are an expert accrual accountant. In most cases you are dealing with aircraft over 15 years old and the historical use, component times remaining and maintenance history will all effect the cost. Most operators complain that they had to spend 30,000 for this part or that part as opposed to doing accrual accounting and saying I "invested" 30,000 in a part which has a life of 4,000 hours and only costs 7.50 per hour.
On a DOC basis, the 500 is less complicated, has the same engine and so I beleive it is cheaper to operate. However, I beleive used 500's have become more expensive in the marketplace than a used 206 and so total cost of owning and operating a 500 may be higher. Aslo, you need a bigger hangar for the 500 as the jet ranger will squeeze into narrow hangar spots due to the head and blades.
Spinwing:
Why do you not like the F? It is the same as a D or E with the exception of a C30 and slightly longer main and tail rotor blades. 650 SHP versus 425. Chews a little more gas in the winter but close to the same in the summer. C30 is actually cheaper to overhaul than a C20R. So for 3 - 5 more gallons an hour, you get a lot more performance. Also, 3200 MAUW versus 3000.