Don't put anything important on them. I have actually gotten a fair share of princos to burn and kprobe resonably well but that is not the only thing to consider. Quality control is very inconsistant with these disks so you have to scan every single disk. They also have bad problems with dye fading and just plain going bad. Some people have had disks that have burned and scanned good that were unreadable within weeks (I have had a few of those myself). On the flip side, I have princos that are a couple of years old that still play fine. You just never know what you are going to get for burn quality and or longevity. They are very inconsistant.
Opps, just realized that you mean you got 300 ty, not 300 princo, but the warning still goes for princo.