Ditto on some of the other posts. Just because a crossbow is faster doesn't mean you can shoot a lot further. I like to think that a crossbow gives you better accuracy and faster speeds than a compound within the same range limitations. A crossbow can sure hit a target at 50 or 60 yards (I've shot a groundhog or two at 50+ yards). BUT, unless you have a rangefinder, misjudging the range by even a couple yards at longer ranges will cause you to miss or injure a deer. Also, like the other posts said, a LOT can happen in the time it takes an arrow to travel 50 yards.

Whether or not the deer is relaxed is a big factor in how far I will shoot. I've had nervous deer jump the string at 20 yards. I've also connected on relaxed deer that were standing still at 30 yards. My theory is the closer, the better. I'd love it if all my shots were "slam dunk" 10 - 15 yarders. However, I would shoot out to 30 yards under ideal circumstances.