I have a Sahara with the SelecTrac. 0 issues and come November time I pop in in 4Auto and leave in like that until May. Will order again when it comes time to upgrade.
The version in the Sahara is not Rock-Trac. So, this will be a new thing we've never seen before.
Make sure it doesn't function the same way that the Full-Time t-cases in the Ram pickups function. I didn't realize it, but those use clutches to connect front and rear even in 4-low! I was under the impression that only the 4-Auto setting used the clutches to slip, but nope apparently ALL the settings except rear drive use the clutches. They've been known to slip and over-heat, especially off road.