4x speed allows you to write or erase the single sided DVD disc in exactly 15 minutes.
As to a good drive, I haven't tried any, but I think you might want to consider the Pioneer DVR, they are the leaders in DVD-RW drives. I heard that the LG is fine too although I never tried any.
I bought a Pioneer DVR-104 long time ago, but I sold it a long time ago. The guy who bought it from me never complained, but you will have to get more opinions from other guys over here.