I asked the very same questions back in July. In Sept I bought a used Hirobo GPH. Great helo.

I have no issues with my OS 46SF-H. It does have the carb mod that is needed though.

What I recommend is to forget about the parts cost. My reasoning is that you'll buy a heli for the cheap parts cost and end up having to upgrade the hell out of it. The Raptor 30 is an example.

Very good advice is to buy a used 60 machine from a local guy that you trust and can fly with. He won't sell you a problem machine if you fly with him each week.

My GPH is a great machine. Very stable in hover and solid in the air. A strong piece of advice is buy a good gyro. Don't skimp. The Futaba GY 240/401 are excellent gyro's.