Seat Belt Problem!

Any new belts should work fine for some length of time regardless who made them. I doubt they will last as long as OEM though. Most common failure with todays seat belts is in their buckles.
Agreed for sure . The buckle problems --durability-wise-- are exasperated by food and dirt finding their way into the clasp ( my work truck for instance ; its buckle is *wearing out* after 4 years / 170,000 miles due to the frequent buckle-unbuckle workload incurred from frequent stops . Then add-in other "people" using "my" truck on Mondays , and their being all sloppy and eating in the truck , and the wear issue is 10-fold ) .

I've had the Mark XV's in my daily driver Coronet for 5 years / 60,000 miles now , and have had zero problems with them . They work just as well today as they did 5 years ago . But , then again , I'm easy on my cars' equipment , work vehicle included ( I operate it as though my name was on its title) .

The "Uni-Belt" setup was / is crap ; I've long maintained this stance . I've had to *deal* with their troublesome action since they were introduced 38 years ago !