If you are going to go through the trouble and expense of installing a selectable locker, install an ARB. It is also known that it will strenghten the carrier too.
The Toyota elocker, could be interesting if you were to find a totalled FJ Cruiser, and you could take the whole rear axle for dirt cheap, remove yours and just install the FJs'.
The elocker motor is vulnerable, and is also prone to debris infiltrating it, causing it to fail. And since obtaining an elocker or ARB from the diff place like East coast is about the same price, I would choose the ARB, actually I did.
I personally know 3 FJ owners, with a failed elocker, that ended up resulting in an exploded diff.
But if I had an FJ Cruiser or 4runner with elocker, i would just keep it until it breaks if ever