I know ridisk are cheap, but again, the problem here is the drive not the disks, surely the fact it works on Samsung drives points that out as you said yourself

Is the Hitachi is picky, that was all my question was.
Also everyone seems to be missing the point, I got 200 Ridisk for £40 so I wont be switching brands any time soon guys, I can cope with one bad burn every 6 or 7 disks you know. Besides I think I have solved it, set DVD decrtyptor to burn at 1X, doesn't make the burn any slower but every single disk has worked in my drive so far.
Thanks for the replys chaps, much appreciated.
I don't think it's the drive. I have a Hitachi with 2.2 FW and I was able to play Verbatims fine until GOW and COD3 began updating via Live when loading up the disc. Now I get unplayable disc errors on both. I never did before the updates. Maybe MS is doing something new. I'm going to flash with the latest and see what happens.