Looks like this thread has received a recent revival.
I'll put in my 2 cents, in terms of function. I recently got a plain-Jane Lone Wolf 9x19 conversion barrel for my Gen3 G32, and so far it seems to function fine, feeding from Magpul PMag 17 GL9 mags (other pertinent details include a Vickers mag release and OE Glock extended slide stop). I got the polished one, mainly so that I can easily differentiate it from the .357 SIG. My main purpose is to use this barrel for higher volume training.
I started off using 10 rounds of Speer's 124 gr. +P Gold Dots for break-in. Thereafter, I switched to Freedom Munitions' new-manufacture 115 gr. range fodder. My friend, who had not shot a pistol in many, many years (he's an Eagle Scout, still active in Scouting, so he has some firearms experience, but virtually no handgun experience), put approx. 50 rounds downrange with it. After the initial 10 of the defensive ammo, the only other time I shot it was to demo. to him the Vickers-Hackathorn 10-10-10 Test, which, embarrassingly, I only scored "81" (out of the 7 ring, I score as a complete miss, and I tossed a shot wide right - I chalk it up to a complete lack of familiarity with the trigger path of the gun: I was going way too fast for how unfamiliar I was with the gun, as my splits were consistently between .43 to .65 seconds...I finished the test with way too much time on my hands). That was shot with the 115 gr. FMs. I'm certain that, total, we put no more than 100 rounds through the conversion.
It should be getting a full workout this weekend as I'm loaning the gun to my friend for an all day defensive pistol class. Average round-count for this class has been in the 400-450 range, from the past few times I've taken it.
I think that as with most reports, mine is also going to be a non-issue, at least mechanically speaking.