Have been using Verbatim 16x since I bought my 716A
Have burned well over 200 backups in that time and never had a coaster or problem..
No problem with quality like the old days when slowest burn speed was "King."
note: that may still be true depending on your rig and slow processor power, ram etc..
I burn all my dvd's at 16 speed and if there is a loss of quality, none of us eagle eyes here have seen it yet.
Don't get too scientific about it.
You have an excellent dvd writer....... Use it to the MAX..