I did a aircraft acquisition course which I found useful for selecting the correct aircraft type on the manner in which it is to be used. Value of an aircraft is not just about cost, but suitability too (although your budget will certain figure into the equation). The course also involved analysing cost of the aircraft over its entire life (as well as the DOCs).
Investing in this sort of education is certainly worthwhile - even if it is for a one off personal purchase. Of course, there are people that you can pay to make these decisions for you if you haven't got the time.
I know its some way off, but if you can wait I suggest attending Heli-Expo in Feb and getting on some courses to learn more about the process. It won't replace real experience, which is what many people in this forum have to offer, but it levels the playing field somewhat. It can give more confidence when going through the actual acquisition bit.
Having said all that, going from the info you have alluded to, I would err towards the AS350, but I also really like the B407 (if you don't need ample baggage space - maybe all your stuff we already be at your destination, such as a second home or whatever).
Good luck,
FFF