ROI
Hi John,
I think you're asking the wrong question.
Start with how much you want, and then see if you can acheive this in the open market.
If you can, all well and good.
If you can't, then are there other factors that still make it worthwhile?
(EG will you fly it yourself? Will you fly your family around as if it were your posh family car?)
If you're buying a helicopter as a piece of kit purely to make a Return on Investment, then don't: buy a JCB and rent it out. (but not just at the moment in the UK.......)
As an owner of several aircraft myself, if you want more advice, feel free to send me a PM.