Aftermarket pistol barrels

Do after market pistol barrels make a difference like they do in rifle barrels?

If you were to upgrade a glock what do you go with?

Sell it.

You're not going to get bullseye accuracy at 50yards with a Glock no matter what barrel you put in it, so you shouldn't upgrade it for the same reasons that you would a rifle. There are, however, other reasons to upgrade the barrel. You can add a threaded barrel for mounting a suppressor, change the caliber (.460 rowland anyone?), but also achieve things like better case support on .40 and 10mm Glocks, or even on 9mm if you want to run super, super hot reloads.

I've done all three of these and been very pleased with the results. I can't say, however, that any of them actually improved the accuracy of the gun to a point where I really noticed it.

OP, no, unless for the reasons stated above.

This is coming from a guy shooting USPSA and three gun, with a stock glock barrel and coated lead bullets.

Depends on the pistol. Glock 10mm's for instance can keyhole bullets larger than 220gr because the polygonal rifling don't always stabilize them properly and the bullets keyhole. Replacing the original barrel with a storm lake, lone wolf, etc. allows you to shoot any and all lead rounds you want as well as larger than 220gr with good accuracy. If you want to feed a Glock a steady lead diet it's not a bad idea because of leading issues with the polygonal rifling. As others stated if you want a threaded barrel then it's the way to go.

I've heard enough to scrap the idea

Spend the money spend the money, you only live once, spend the money

On ammo... and match fees.