No reason you couldn't run beadlocks on just the front, other than having non-matching wheels. You will always have a better chance of debeading a front tire vs. a rear tire because of the lateral loads on the fronts when turning.
Beadlocks are generally heavier, more expensive, and require a little bit of maintenance. The maintenance basically consists of making sure the bolts on the lock ring are tight periodically. In regards to mounting and dismounting tires it kinda' depends. With most beadlocks you can unbolt the lock ring and the tire will slide off the rim with minimal effort, so no special tools are required. However, with a $40 Harbor Freight tire changer I can mount and dismount a SxS tire on a non-beadlock rim much faster than I can on a beadlock. For those of you who have never mounted up a set of beadlocks it can take quite awhile to get all the bolts properly torqued down.