Plenty of opinions on what locker to go for.....do your research on the diff types of lockers that are out there, even to the extent of going to different outlets and have them run you thru there product, and while your at it ask them to show you there work shop and walk you thru how it will be fitted.
I have mate who runs an outlet down in Newcastle, and he takes all his customers who are having lockers fitted into the work shop, and meets the workshop supervisor, and he then has a good talk to them about the product, and walks them thru whats required for it to be fitted. A good initiative I think.
IMO all the diff brands of lockers are an asset to any vehicle, and you will defo notice the difference when you need to use it the first time.
I run an ARB air locker, I have only had it for short time, but have had no dramas, I choose it because of reputation pretty much, to my mind they have been around for a fair amount of time, and plenty of trucks out there use them with plenty of success, that's not to say that other brands wouldn't do the same.
Also check out prices mate, they vary greatly from shop to shop.....haggle hard....
Good luck which ever way you go, youll love it.
Swanny