[dkfick]

I use plastic, stainless, and glass.  I do believe plastic poses a bit more of a risk of harboring bacteria in scratches.  Not all plastic or plastic fermenters are created equal though. 

I believe the real risk of those scratches in the plastic come from the scratch being made, then a yeast or bacteria gets in there, then you wipe it folding a the gouged up layer of plastc back over it thus preventing much sanitizer from getting in the scratch.

Now PET Better bottles for example this is much less likely as you can't really rub anything inside there.  They are also a much harder plastic than the white buckets... That said I do use the wine buckets quite a bit... Though I do replace them maybe once a year.

[Saccharomyces]

the last couple of batches produced an off-flavor that a beer judge identified as a contaminant due to fermenting in plastic.

I sounds like you are using Star San as your primary sanitizer.  Fill your Better Bottle with 2 oz bleach and water, and let it sit for 24 hours before rinsing.