I gots thousands of shots through my B19, and the barrel is as good - or better - than it was the day I bought it. Even though it's Chinese, it oughta last you just fine. Besides, it isn't too common to have ready access to replacement airgun barrels, at least at any reasonable price. Barrels for Beemans and RWS can easily run half the cost of the gun.
Just don't go "fire lapping" the barrel using valve grinding compound. Like I did on one of mine :-(
Pretty much all the other parts are interchangeable with the standard Quest 1000, so you're covered there.