It’s my understanding that lead bullets are not recommended in a Glock pistol with a polygonal barrel. If this is a myth, which it could be, then somebody change that paragraph in Wikipedia's discussion of polygonal vs. rifled barrels.
http://en.wikipedia.org/wiki/Polygonal_rifling
Of course, shooting reloads of any type, in any barrel and in any firearm is not recommended either, but some of us choose to ignore that part of the owner’s manuals.
Google polygonal vs. rifled barrels for some additional reading.
Proper care and frequent cleaning are perhaps the key factors.
I've been pleased with Berry's plated bullets from Powder Valley (they have lead too).