also there is the factor of weight, the double is lighter than the triple. Some people will also argue about the q factor, which is the measure of distance between the crankarms. The last thing is how well the thing shifts. I don't think this would be an issue if you kept things well maintained, but can become an issue if things aren't kept up with. Compact cranks seem to overcome the problems of the triple and give you the lower gear combinations, it is basically a double chainring, but instead of a 53/39 upfront it's a 50/34 or 50/36. Just something else to think about.