I burned ( on my Liteon SHW 160-P6S with FW PS0A with Anydvd and clonedvd2 once and anydvd and clonecd twice) a dual layer dvd 3 times with HP dual layer and got 1 coaster, and two dvd's that stopped playing at chapter 4. I ran the disc quality test with nero and the best of the 3 came out as a 45 on quality and actually froze mid test no matter how slow i turned the speed setting at for the test to run at so it never even completed. I tried a scandisk and it hung up on the scan after a cluster of bad sectors.
I then burned the exact same DVD (anydvd to clonedvd2) one time on a verbatim dual layer and it came out with a rating of 95 and plays flawlessly on both my TV's players. The kicker is that i ran the quality test on teh store bought DVD just for curiousity sake and found that it also had the exact same quality rating and the PI errors and Failures were identical.
Bottom line, i'm sold on Verbatim. I tried to save a buck on the HP's at walmart but it's just not worth it. Verbatim seems to be exactly the same (at least according to Nero) quality as the ones used by the original factory burner.