OS X :: Burning Data DVDs - Discs Not Able To Read By Mac

I'm having issues with burning data DVDs on my Mackbook Pro (running Snow Leopard) I'm burning large files (DVD/Blu-Ray rips) and the discs are unreliable. I'm trying to pinpoint the problem but haven't been able to. Some of the discs are not able to be read by the Mac - sometimes it spits the disc out a few seconds after being inserted...other discs just spin and spin and spin and it seems the Mac cannot read them - I can't even eject them without rebooting the computer. There seems to be no rhyme or reason between discs that read OK and discs that don't. Some discs were burned via the internal superdrive and some via a Sony USB dual layer burner. All discs burn and verify OK - there was no indication on any of them that anything went wrong. I am using Sony and Memorex discs, single and dual layer. Are there any known issues with either the Mac superdrive, or the burning of large (4+ GB - almost 8 GB) single files? I've got a good number of discs here and like I said all burned OK...but I've been having to go back to retrieve files and am only now finding that some of the discs are giving the problems described above, which means many of the backups I thought were legit are no good. Alternatively, if there is a better method for backing up these files . They are stored on hard drives being used by a streaming video player. I thought backing up each file to DVD would be a reliable backup method but apparently this is not the case. It's not ideal to back up to other hard drives - there are too many files and it would be too expensive. I don't know that online backups would be feasible because of the amount of time it would take to upload them and the space they would take up would likely be too expensive to maintain.