wow... such debate over this! not that i expected anything less. i think that for the MOST part, everybody has posted something relevent. there is some info that seems like it is less factual and more opinion, which is fine, but it seems like some is kinda backasswards. bear with me on this one cause i know its not the standard way but an option is t lock the front. the only reason id lock the front before the rear is cause this way you can have a lunchbox locker that is "selectable". what i mean is if you find yourself on slippery roads, because of the open diff., only one tire spins. so you engage your 4wd and now if there is and tire spin, your going to have the locker there to help. so in a weird way you make it so the locker is only available when you need it... i honestly wouldnt lock my front before my rear, but its a way to spend less and still havea "selectable" locker...
if you add a locker then your vehicle is no longer stock. so it wont drive like its stock. getting used to how your vehicle does preform with the locker is more vital than anything. you can talk about the physics of how a locker changes the driving experience, or you can be well aware of that fact when you go out and practice. honestly i think that winter would be an ideal time to install a locker. this way you can go to an open parking lot, or a back road and really get a good sence of how different it is. the snow/ice seems like a good way to test cause you probably wont find a more consistant, slippery surface. idk, i dont have a locker, so really im just saying what makes sence to me, please correct me if im wrong!

 

^^^Those who can't drive with a rear locker in the snow also can't drive with a front. They think it has a tendency to be locked turning and basically make you understeer slide off the road. I'm locked F/R and never had an issue so take all opinions with a grain of salt, everyones driving abilities are different.

 

haha, yea, fair point! having the front locked will cause less predictable opperation. but your right, if you have a hard time with the rear, the front wont be any easier. the though was really about havening a lunchbox locker that would have the selectable lockers convenience... it was just a random though... what company did you go with for lockers?
there was a post that was talking about how much easier drifting was w/ the locker... it made me drool. i love to drift but that open diff makes it so hard to get a consistant, powerfull slide. this was the first winter ive owned a 4wd rig.. till now it had been all FF's. and drifting with an FF isnt really drifting, thats not to say its not fun, cause my saturn (5 speed, only redeming quality) got the **** drifted out of it last winter. wow! not to boast, and be totally off topic, but i had so much more confidence in that thing. i was getting up to like 50mph on most roads... sideways... idk, having a RWD makes the end swing a lot easier, so iguess its just a matter of gettting used to that... im getting there. i no longer just swing a 180 when attemping to drift... but i digest...

 

Its night and day when drifting with a locker, and i thought its easier to control once you know how it handles. I have a manual so to straighten out you push in the clutch, want to turn more well just give it more gas. I would scare the crap out of friends when i took them to a camp ground and drift around the trees, benches, power outlet thingys and those crappy grills that are cemented in the ground. I dont mean to brag but the locker gave the confidence to slide thru 2 obstacles at 25mph sidewards with only a few feet to spare. My gf wont let me take her back there anymore hehe

 

It's nothing unique to a locker but rather any traction enhanced diff. An OPEN diff (99% of vehicles) is just one wheel spinning (torque applied to one wheel or the other) and the other is just a boat anchor. A traction enhanced diff is one where torque is being applied to both wheels, equal or unequal, but still being applied. There's a number of different types of lockers and limited slips but they're categorized as traction enhanced diffs. Basically a diff is either open or traction enhanced in some form/fashion.

IMHO, some form of a automatic traction enhanced diff is preferable in the rear 1st, that way it's usable regardless of conditions.