My GSA-4120 is my second DVD writer.
I had the Nu-tech DDW-081 before, after it got rave review on site.
Big mistake, it had tremendous problems reading back (crappy, but even ones written by itself)) DVD's, would sometimes create spurious errors on Arita RICOHJPNR01, even on my Verbatim DVD+RW I bought for backups in the first place. I just couldn't trust it.
I love the GSA-4120, no coaster so far (100+ written) on several media:
Arita 4x DVD+R RICOHJPNR01
DATAWRITE 8x DVD+R PRODISC R03
Platinum 8x DVD+R RICOHJPNR02
Arita 2.4x DVD+RW RICOHJPNW01
Philips 4x DVD+RW PHILIPS 041
Verbatim 4x DVD+RW MKM A02
Only one problem encountered so far when I had an DVD+RW written by my brother's NEC 3500; couldn't read it or even format it. After complete format by the same NEC, my LG still couldn't access it. Another NEC 3500 at a friend's formatted it again, and finally I could use it again. Very weird indeed !