To put some numbers on Tulwar's argument. If you want a +3 stat enchanted (with only one stat you're shooting for, thus increasing the potential number of tries needed by a factor of 6) GLORIOUS armor, you'll need, on average, (1/.1333)*(1/.16667) = ~45 attempts. Of these 45 attempts, 20% result in a failed attempt that destroys the armor. This means you'll need to purchase (via BG points) 1+(.2*45) = 10 glorious suits. That's 3000 BG points.
For the BG armor sets you will need, on average, (1/.1091)*(1/.16667) = ~55 attempts. Of these 55 attempts, 34.54% will result in a failed attempt that destroys the armor. This means you'll need to purchase (via BG points) 1+(.3454*55) = ~20 BG armors. That's 9000 BG points.
This obviously does not include later refinement failures (since those will apply equally to both examples given here - although it increases them by a multiplicative factor making it "worse" for the class-specific armor sets).
We can debate the various levels of restricted use for each set, but the difference in costs (benefits of each set are up for debate) is pretty clear - and sad