4 wheel drive system differences

[IdahoRunner]

So I picked up a super low mileage '96 Limited a month ago. I noticed that it has a similar 4 wheel drive system as my '99, both have diff. lock, but the '99 has a center diff. lock as well as a rear diff. lock. and my '02 has a center diff. lock as well as the ATRAC.
Question is, both the '96 & '99 have rear diff. locks but the '99 has a center diff. lock as well. Is there a significant benefit that the 99 has over the rest?

Here is a driveway shot of the '96 & '99.

 

[GatorGreg]

Compared to your '96, your '99 Ltd has the added benefit of the so-called "multi-mode" 4WD system which allows you to run in 4 Hi on dry pavement all day long, something not recommended on your '96. Multimode first appeared in '99 as std feature but ONLY on Limited 4WDs. It didn't get added to the SR5's until the '01.

Compared to your '02, your '99 has the optional rear locker which was no longer available after '00 model year. However your '02 has the benefit of A-TRAC (which started in '01). Lots of debates here about the merits of rear locker vs. A-TRAC, with the off-roaders generally favoring the rear locker and the on road safety wonks generally favoring A-TRAC / VSC. Of course, when the '09 Trail Edition comes out we'll finally have the option of getting BOTH

JA's site has excellent year by year analysis:

http://www.top4runners.com/ja/runhist31999.html

Also, your 4Runners look great by the way!