non-steel frames and longevity Until recently, I had a late 80's Schwinn aluminum frame bike (now a thief has a 80's Schwinn aluminum frame bike, but that's another story). I had heard a number of horror stories about early aluminum frames--that the welds weren't properly done, or that the technology hadn't been perfected yet, that one should expect the frame to come apart any day, etc. I assume these kinds of rumors are being spread about carbon frames as well. Is there any hard evidence here? I know this is very hard to quantify because there were dozens of manufacturers, and there are/were lots of technologies being used. But is there any evidence, or is it just a cloud of Fear Uncertainty and Doubt?
I ride aluminum frames almost exclusively and have had no problem with them.

The welds are what tend to break first on most bike you hear these horror stories about, but this can happen with any sort of weld (though some forms of welding are more effective than others), so if a bike seems to be too good of a deal to have an aluminum frame, make sure to check out the welds, for those could very well be the deal breaker.