Ok, that's enough informed consent. I'm now going to tell you what material works best for a mountain bike frame - Aluminum, Steel, or Carbon. I base this wisdom on two weeks of recrimination after Akerloff's information asymmetry and rampant bike lust  got me a problematic Carbon Frame Cannondale racing mountain bike. During this time I sorted out how to buy a used mountain bike and why Carbon frame warranty loss hits resale value -- and I came up with the definitive guide to the BEST frame material:
|Retail $ ||4||2||1|
|Repair $ ||1||1||3|
The spider graph  makes it clear ...
What do you mean there's no clear winner?!
Year, it's like that. Since I don't race and don't have time to spend on fussy stuff I'd be best off with an aluminum frame or, if I had the money, a steel frame from one of the elite Minnesota steel bike companies. Still, there's no denying the performance and comfort of carbon.
So it just depends.
I lied. Sorry.
 My brother bought a Porsche under similar circumstances. He says I got off easy.
 In these cases higher rating is less cost. Carbon can be relatively cheap to repair if you can find the right person or don't mind mailing a frame.
 It is really quite amazing that one can create a table in Excel/Windows and paste it into Blogger's composer window as an HTML table. I don't think I can do that on my Mac. I tried to do this graph in Google Spreadsheet but didn't seem to be supported there.