I don't know if I would go as far to say the 407 is more reliable, have had more problems with little things going wrong while flying them than I have in squirrels, but I am sure there will be someone with an opposite opinion.
If you intend to do night flight, the gauges in the 407 will not impress you at all, and I have had quite a few problems with gauges or senders, and the LCD gauges are not cheap!
If you have snow deflectors on the 407, and you want the heater on, (which go hand in hand) It seems to suck in exhaust smell into the cabin when you are on the ground.
Grease every where - as it has expensive pitch bearings that need grease and then it gets tossed every where.
These are not big deals, but just little things that bug me about the 407, really the only good thing I can say about it, is that it is better for long lining out of than the squirrel.
From any engineers I have spoke to about it, the squirrel is a lot easier to work on than bell, I think it was designed for engineers really.
I don't know how many hours you think you would do a year, but as a private ship I'm not sure if you would have to many maintenance issues if not doing 100 hours a month?
To cap off
I personally have had more maintenance issues with the 407 than squirrel in general.
I enjoy flying the 407 with a line on, but if I had to use a heli for more passenger/utility/private type work I would choose the squirrel (if I had the choice).
Oh, and from what I have seen, the 407 is in just as much demand as the squirrel at the mo, so both are demanding hi prices.
my 20c worth