Originally Posted by velocipedio

the problem with a triple is that it can be very difficult to tune your shifting for two reasons: (1) the long throw of the front derailleur compromises the chainline, (2) the long cage of the rear derailleur and the extra chain makes for sloppy rear shifting.

triple advocates [usually people who bought triples and want to be validated by your choice] claim that the shifting on a properly tuned triple is "just fine." the problems are that it will never be better than "just fine" -- not "crisp" and "amazing" -- and that it is quite difficult to get a triple properly tuned. a lot of bike shop mechanics don't know how to tune a triple, and those who do frankly can't stand doing it, it's such a bother.

if you need a low gear, you have two better options. the simple one is to just get a cassette with a bigger gear. a standard shimano rear dereilleur can handle a 12-27 cassette, and the 39x27 combination gives you all but two of the lowest gears you'd get with a stock triple with a 12-25 cassette. this will probably cost nothing at the time you buy your bike... maybe $30 as a later modification.

the other option, as racerx points out, is a compact crankset. this is becoming a popular option, since few recreational rider -- even pros -- ever use the 53x12. a 34/50 crankset with a standard 12-27 cassette will give you about all the low gears you need to climb the alps without sacrificing shifting performance.