I've run welded gears, a trail tough mini spool, selectable lockers (but never in a Samurai), and a lock-rite.
I really disliked the lock-rite I had in the rear. It worked great off road, but was really unpredictable in town. If I wasn't really on the gas, sometimes it would lock and other times it would ratchet...I never knew when to expect it and at times it could throw me toward a curb or ditch. You can live with it, but you really notice that it is there.
The welded gears or mini-spool are very predictable, and there is so little play in the mini-spool that the tires don't usually chirp on pavement. The mini-spool is relatively cheap and easy to install. You do have to reset backlash on the gears, which requires a dial indicator...although I did about 10 sets just "by feel" before I bought a dial indicator and never had a problem.
I've had good luck with longevity with welded gears; one broken side gear. I have tried to weld the gears 2 ways; by welding the side gears to the housing, and by filling the spider gears and side gear teeth with weld. Welding the side gears to the housing is more difficult...one side is nearly inaccessible with a MIG welder or TIG torch, and the other side is severely limited in how much filler material you can use because of the housing cover. Welding the spiders is easier, but leaves a little bit of play in the gears and always eventually breaks the teeth off of the gears (although it may take years of abuse).
Selectable lockers are, of course, the best of both worlds (open and fully locked), but of course are the most expensive. Also requires setting up the gears after installing which costs $$ if you can't do it yourself.
IMO, go for the mini spool. It is the most durable, easiest to install, and cheapest (if you don't own a welder).
