Good burn or bad burn?

Just been burning a few DVD and have been geting some slightly odd results and was wondering if people would class them as a good burn or a bad burn (unfortuantely i’m on a different machine so can’t upload the .png’s)

One burn i have has relatively low PI failures for the media type and a perfect speed read graph however when i but it in one of my other 2 burners the PI failures are huge but they do again have a perfect speed read graph.

My other odd burn has to many PI failures for my liking when read in the burning drive and again worse results in my other drives. But also again it has a perfect speed read graph.

So what gives? (using CDSpeed if it aint obvious)
Suppose my really question is what does PI failures actually mean and is it important if i’m getting decent speed read graphs?

[As it probably makes a difference the media is Infiniti +R DL and the writer is the new LiteOn and my other two drives are Samsung and a BenQ]