If I had the spare cash I'd fit a locker in the front every day of the week. I don't really understand the concern. If you have the locker your rig will be that much more capable. If you're heading into a tight section where turning is more important than traction just flick it off.

Just like picking a good line or the right gear. Sometimes you get it wrong and need to have a second crack.

My old fourby was front and rear locked and I miss it all the time. I do remember flicking the lockers in and out on some tracks where I had to get around some pesky trees. I've not used one, but for the same reasons I wouldn't bother with an auto locker.