The Optiarc 7240s gets recommended a fair amount around here. May not be quite as good as the 7200 series, but the 7240s is still readily available, while the 7200's have disappeared. My 7240s is not a reliable scanner, so you should use your BenQ's for that. It uses a SATA interface, not IDE like your older drives, and it has a rather abrupt mechanism when opening the tray.
I've had very good results using high quality single and double layer media, but I burn at moderate speeds...usually 8x for Yuden000 T02, 12x for MCC 004 and 4x for MKM 001 (Verbatim DL 2.4-6x speed disks). I don't use mediocre media, so I can't advise you on that.
If I had to buy another dvd burner right now, this Optiarc is the one I would choose amongst the drives that are available.