I actually went the opposite direction a few years ago, from perfectly functioning compact double to compact (I guess) triple (50-39-30). I kept my 12-27 cassette, got a slightly lower low gear, high end stayed the same. Kept my short cage derailleur, since I don't really care if I can use smaller than 23 rear on the granny ring. I mostly use the middle and large rings. It shifts better than the compact double ever did. My chains seem to last a little longer, maybe since I spend less time in the nearly cross chained gears (or maybe I'm just getting older and not pushing as hard!