Hi Folks, Aussie Locker here...
We have sold many, many JK front and rear lockers with customers reporting great success offroad and on road handling.
To address some of the questions here:
2WD - The front driveshaft in a JK (for example) is always turning, even in 2WD. This causes the locker to click in turns as it unlocks but it does not have other locker handling because it is not getting hard lock from the driveshaft such as when in 4WD. The only steering issue in 2WD is the "possibility" of the chunka/chunka (binding in very tight turns). So the answer is that there may be a click in turns and in very tight turns "some" vehicles can experience binding and the resulting sound associated with that. Slightly backing off of the tight turn radius will relax the binding and the sound/handling goes away
Ice Driving - We do not recommend using a front locker if you intend to drive in 4WD on the road in icy conditions. Most folks report not needing 4WD in winter conditions with a rear locker pushing them along.
Rear Lockers - The Aussie Locker JK Dana 44 has an excellent track record since release and we haven't had any reports of failures. An automatic locker for rear axle applications are a great choice because of cost, ease of installation, and both on and offroad manners. When someone asks which they should do first, I recommend rear lockers, especially if they don't have manual hubs or if they drive in winter conditions.
Hope this helps, feel free to shoot me an email, pm or call with any questions.