The True-Trac is not an actual locker, but a limited slip. It is Detroit's name of their limited slip, or Posi. The nice thing about it compared to a Posi-Traction limited slip is it uses no clutches, but all gears.
It is ideal for front applications.
All things considered, if I needed something in the front of a frequently daily driven vehicle it would be the choice. BUT, if you take out the $$$ factor I think ARB, or better yet The Toyota cable locker would be the way to go. (But Mr T was not kind enough to allow us in the USA to have those)
The thing to remember is with a vehicle with front disconnect hubs, the locker, LSD, spool, whatever only comes into play when the hubs are locked in. The Lock-Right, Aussie Locker etc are "probably" cheaper and are easier to install than a LSD, and as long as the hubs ar not locked, are not noticed. Now, if you lock the hubs in, they are definately noticed. Plus the Lock-Right, Aussie etc are actual lockers, versus the limited slip. The Lock-Rights I have owned were always purchased as a temporary, economical way to get the traction I wanted, with drawbacks. The best luck I have had with Lock-Rights have been in Toyotas. The worst luck I have had with them were in GM and Ford. (S-10 and full sized Ford) I think the reason for this was that Mr T made the Toyota diff a little better than the GM and Ford vehicles I put them in.
If I had to drive a vehicle in 4WD on a road, and traction was required the True-Trac would probably be the choice I would make. BUT, I like being able to have the option to turn it on and off. Even with ARB's and Toyota electric lockers, when I use them on road or off, especially in off camber, slippery situations, I find myself turning them on and off frequently. MY rule of thumb is to only turn on (or lock the hubs in) a front locker when needed, especially on road.
Also, in my experience, a locker, LSD, etc is much more noticable in a shorter wheel-based vehicle such as an fj40, compared to a wagon, 4-runner, full sized truck, etc.