I have a LW 5.15" barrel in my Gen3 G20. And it's fantastic! My pistol has never shot one round with it's OEM barrel.
But I did detail the LW before I shot it. I polished the feed ramp and put a fast lap on the chamber and barrel. I broke the pistol in on some full house 10mm I had loaded up years ago for my early,,, worthless,,, can't wait to break and go home DE. I had two jam's in the first mag. And nothing since. It should have been a option from Glock IMHO. And the brass. It always looks great!
My 5.15" LW is great. After it proved to me it was for real. I polished the barrel and chamber a tad on the outside. Damn G20 has some bling.
I can't weight to buy a LW 6" tube for my pistol.