TapADraft or other PET bottles: flavor retention?

Hi, all! Based on the (generally) very good reviews here, I pulled the trigger on a couple of the TAD sets (I want to be able to have more than one brew on tap at a time, so...)

My question is in regard to the TAD bottles, but I'm sure it's the same answer with ANY PET bottles: how badly do the bottles retain the flavor of what they've previously held?

The reason I ask: I'm pretty excited about not having to pasteurize ciders and hard root beers. I'll naturally carb my beers to save on the carts, but for the backsweetened stuff I'm going to stabilize, sweeten, and force carb. I've heard that root beers are awful for "flavor staining" keg lines and whatnot. Safe to assume the same will occur with the plastic bottles? What about the taps? How about with ciders?

Thanks!

Ike

I have never made rootbeer or soda, but I switch back and forth between cider and hoppy beer in my TAD all the time and have never detected flavor carry over between batches.