Our housings are different because of the IRS on the Armadas. However, I think the internals are about the same.
The failures on the Titans have been in the spider gears. I haven't heard of any ring gear/pinion faliures, or bearing problems.
There may be a reason the Titans are seeing failures and not the Armadas. When you are driving in a straight line without wheel spin the spider gears don't rotate. But if you have one wheel spinning the spider gears are rotating very fast. I think the Titans get more wheel spin than the Armadas, putting much more demand on the spider gears. The Armadas have less wheel spin for a couple of reasons; more weight on the rear axle and the independent rear supension. The Armadas have better traction than the Titans. Also all Armadas have VDC and Torque Control which limits wheel spin, many of the Titans don't have it.
I don't like the construction of the spider and side gears. They are powdered metal construction, not machined from a steel billet. While powdered metal technology has come a long way I would still like to see the spider/side gears machined, like the ring gear and pinion.