Nope, mud is about traction, either will be effective but lockers are better, you can still spin them. Snow lockers better as long as it is deep enough to get a bite if not, open diff will keep you straighter then either locker or limited slip. Sand, not as aggrieve tires, air down, traction is not an issue, staying on top is. Look at dun buggies, they aren't even 4wheel drive.
There is nothing wrong with true tracs, I would rather have them over auto lockers but not selectable lockers such as the rubi has. Plus the gearing is a big deal. For the OP a stock JK or TJ would probably be adequate BUT if he get bit by the buy and ends up building his Jeep the rubi has allot already done from the factory and for the money a good deal as opposed to going out adding selectable lockers, re-gearing you axle and your TCase.
having selectable lockers allows you to unlock increasing you maneuverability.
Where your proof?
PS, I have an 01 sport with a D30 like you have, D44 in the back. I also have ARBs and have re-geared. That was expensive. Getting it in the Rubi is $$ a good deal.