Good bars, they wear more or less like the Windsor Speed Tip and Oregon PowerMatch bars. Fairly heavy for their size. Paint is hard so it promptly chips off, so if you're into keeping your bars all shiny and new...look elsewhere. Tips are securely attached with more than one rivet (Brilliant idea, Oregon...), which is nice.
The GB Titanium bars are the thing, though, and they only cost a few bucks more than the ProTop bars (until you get into the long bars, anyway). Quality and wear are similar to Cannon, but at a much lower price.
Drive link counts are sometimes a bit different on GB bars than on other brands of bars of the same stated length. Sometimes they want a link or two more or less than you'd expect, and sometimes they even want something different from what's stamped on 'em. Or so has been my experience.
Regardless, they're good bars!