I would not spend the money on an ARB unless I won the Powerball. While 4-wheeling - flipping a locker on and off never made sense to me, and I never felt like disconnecting a locker, front or rear, would make any difference on the obstacle I was on. If an ARB is a choice for a daily driver and wheeler, it makes more sense to me to install one in the rear diff.
Lockers, of any kind, will always want to push you in a straight line, which in my experience, will often push you off the line you wanted to be on, or making it hard to take the line you want. While this is less of an issue for the experienced wheeler, it can be a PITA for the novice/intermediate wheeler, and for those spotting them, as they don't have seat time necessary to compensate for this. I wheeled open diffs for almost 15yrs, and after 15yrs of running lockers, I still prefer wheeling an open diff as the default setting, for me, a selectable locker is no different than dual cases,and engage them only when only when needed.
I don't really want to spend the money on the ARB personally. I am really interested in the truetrac though. I have heard good things about them. I am not a hardcore wheeler as of right now but I want to be as I slowly get practice in over time! I don't really know what I am looking at though when searching for one? I tend to overthink things a lot when buying stuff. Do you have any experience with a truetrac Gnarly? Do you maybe have a link to a website that has em? I don't like asking for this sort of help cause I dont want to waste anyones time or become a burden/annoyance. What would I have to do to install one? Do I need any replacement parts? I am slow on understanding how stuff works on vehicles. I will probably be having a shop install it to be safe and not ruin my gears by doing it myself.
As Gnarly mentioned, trutracs are good, but getting them to engage when needed can be an issue, if you had dual cases, or an auto trans, it would be better, as you can use the brakes to engage it without stalling, a hand throttle can help with this. If it is one or the other, I would go with a standard mechanical over the trutrac.
A new ARB isn't your only option, the Toyota e-locker is also available, and can usually be found used for about $600, though it does take some slight modification to the stock housing to install it.