Petroworks used to sell the Detroit, and it's what I've got. Detroit no longer makes the Samurai locker, and PW now offers the Lock-Right by Richmond Gear. Based on users' reports, they're pretty similar. The version WITHOUT the replacement side gears seem to work better -- reuse your OEM ones.
There's also a newcomer, the Yukon Spartan. Too soon to tell, unless someone with direct experience is willing to opine. AFAIK
, these are the only two options for "lunchbox" lockers. TrailTough has a great intoductory price on the Spartan. I'd call Brent (@TT) and ask about them -- he'll tell it straight. You can google for comparisons between the two.
Edit: I chose to put my locker in the rear 'cause I'm climbing when I lose traction. In the rear it's full-time and does affect daily driving, so I've learned to adjust my driving style to accommodate. I put a Limited-Slip in the front so that steering would be less affected, even with power steering. Also, I'm concerned that, on a daily driver, a rear LSD would wear out quickly and they are no longer available.
Edit 2: Another factor to consider is that the 22-spline Samurai front axles are not as tough as the 26-spline rear axles. With a front locker, Trail-Tough's Double-Tough front axles might be a good choice.