I prefer PET as it is less likely to hold the smell of the prior liquid. They arent the best for reuse as they are harder than LDPE and will crease. I get mine from this fella: Link
I also use PET as i feel they are less likely to "leak" the aroma's, not a physical leaking but a leaching causing the flavor in the bottle to lessen over time.
EDIT: BTW, this fella ships very quickly and the product has been in excellent condition every time.