Howdy all - I have a 10-year-old Rocky Mountain Metro 50. My LBS tells me my drive train is shot (I've put a lot of miles on it). To install a new drive train will cost $400. The bike when new cost under $700. Should I put the money into it or go for a new bike? Not that it matters all that much but I'm considering a Specialized Crosstail Elite disc or Cirrus Elite Disc. Thanks for the advice.