In a general sense (not neccessarily this particular issue) I think the biggest problem is press issues...most presses are not designed for the extreme parallel limbs...and most shops I go to do not have a proper press..they are presses that are a few to several years old.....you should back the limbs out in those situations as much as possible. Apple and some other folks are starting to build presses that are designed specifically for the parallel limb bows..My shop bought a new apple press last year and modified it's existing press to handle the Mathews and BowTechs w/ parallel limbs.
As for the BowTech limbs...I've had a dozen without any problems myself and I've pounded the $hit out of them..most at 5 grains per pound or darn close. But as Vic said, the material is from Gordon, and once in awhile Gordon makes a bad run of glass...Remember the Hoyt Redline & Powerflex limbs? Blew up left and right. Gave Hoyt a bad name for a couple years, but the problem was with a huge shipment of Glass they got from Gordon. If people are going through multiple sets of limbs, either the shop/customer is doing something stupid or there is a problem somewhere else in the bow..rockers, pockets, twisted riser, etc.
Limb failures are a fairly common thing from all manufacturers, and the more bows they sell, the better your chances of hearing about them simply due to the law of averages. If I had to base my bow buying decision on choosing a company who I've never seen a limb failure from, I'd be shooting a rifle
