I have owned MANY Gibson acoustics, but never a Martin, so I really cant comment. I have tried many Martin's at the shop, and there is no doubt they are incredible guitars. Gibsons are the best sounding and best looking, but they don't seem to play as smoothly as a Martin.
If I were on stage, I would take the Hummingbird. If I were only in the studio, I would take the Martin. Both hold their value very well if you buy used. You really cant go wrong either way.