I would go for the 8x DVD-R Traxdata's (Ritek G05). In my experience the Traxdata branded discs are generally of good quality.
The reason is pretty obvious if you look below. It is not easy to get a better burn than this one, even on expensive media, and I don't think a Ritek R03 can beat it (I haven't got Ritek R03's so I can't say for sure) ...
1. You can get the same nice burns starting with FW2.18 (or newer).
2. Earlier FW's were not this good (e.g. 2.27, 2.16).
3. With 2.TB you can also burn this media at 12x, but I haven't tried it yet.
So, here we go ...
Traxdata 8x DVD-R, 25pk spindle, RITEKG05 @ 8x (NEC3500, FW 2.TB):
Burn time: 9:42 min