It looks as though both the compact double and the triple can provide decent ratiometric progressions, with no inordinate gaps. With the double, however, you may find yourself doing more double shifts (going across several cogs in back while changing the front). If you are accustomed to a 30/27 low gear now and feel as though a 30/24 would be an acceptable alternative, then the compact double's 34/27 should suffice.
Some folks prefer the double's Q-factor, which places ones feet closer together and may be easier on the knees for that reason.
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069