I bought 500 Prodisc CD-Rs from STI Certifified.
When I burn them in the internal burner with iTunes in my MacBook Pro, I can burn one OK, but then the next disc is ejected without any error message. I have to reboot to burn the next disc.
I'm burning audio CDs. Whenever I burn one, I play the first few seconds of each track to ensure that I have a good burn. Sometimes when I do this, the tracks advance quickly without any sound being played. Again, rebooting fixes this.
Sometimes if I eject the disc and reinsert it, Mac OS X complains that it's a bad disc, and wants to eject it - but rebooting fixes this too.
I tried some other Prodisc media from a previous purchase, that I had nothing but success with, and it has no trouble now in my MacBook Pro's burner.
This all still happens after bringing all my software completely current with Software Update.
I also have Blue and White G3 Mac that I installed a Pioneer DVD/CD burner in. It burned several CDs in succession OK, then got stuck with iTunes saying "Initializing". I wasn't able to get it to stop or eject the disc, I had to force-quit iTunes and then reboot.
I also have Toast Titanium, and plan to try it, but haven't yet.
If you'd like a free copy of my CD Geometric Visions: The Rough Draft email your snail mail address to email@example.com I'm a bit backlogged now, but you'll get it eventually. I've given away about 2500 so far.