Selectable lockers are always more flexible...I never had a locked X, in the Jeeps, I can tell you that you have to pay attention to the conditions when locked....icy off camber for example is a real test...the locked tires tend to crab down hill, and if trying to make a tight turn, the locked fronts tend to push wide on the turn.

On road, the tires can chirp, etc on turns until you get the hang of accel/decel factors that kick in the lock.

In short, there is a learning curve for driving a locked rig...you do get used to it though, but it is a compromise of capabilities.

If you are willing to put in the learning time, it would work for you, if you are worried that you'll get into too much trouble in the process of learning, then the selectable locker is a better choice.