I have a bike with 50-34 compact crank and 10 speed 11-34 casette. It's a 105 group with an LX mtb rear derailleur. It works ok, But I like the close ratios of my triple equipped bikes better. I like climbing a lot more with the triples. I agree with the others about bigger jumps in gears on the compact crank bike. My 11-34 cassett makes the jumps a little worse. I would not sell a compact crank set up just to go to a tripple.