The top four common barrels under $50 that I hear of very often are the Smart Parts Progressive and Tear Drop, the J&J Ceramic, and the Custom Products 1 piece. All are good barrels and it all comes down to preference.
I just got my Tear Drop barrel and put it on my System X. It's just too bad that when it threads all the way that the logos aren't displayed correctly and it ends up the Tear Drop logo is facing down while the Smart Parts logo is facing up.
