BSA barrels can be good, can be bad. They can be put in correct way round, or back to front. If you are lucky you can even find some pcp's with re blued barrels where the original s/n appear to have ben filed off () 'from' factory ! Some in right way round, some not !

Springer wise imo:
Superstar - Good
Airsporter RB s Good
Late Mercury's Good
Others - pants, ranging from a bit ropey, to shite, some design floored (over sprung from scratch for 12ftlb), others just piss poor QC

I like BSA, I have several of their pcp's. They are extremely pellet fussy in 177, and sometimes 22 too -
I think that getting a designer to design them was a great move after the springers, pity they didn't follow the designs more accurately or find better manufacturing compromises sometimes though -