Odds are, if I had been able to find the soft #2 plastic white Nalgenes, I would have bought them and stuck with them. I understand the concerns come from the #7 hard types, and since the #2 is basically thick milk jug material, I would hope it is safe.
I didn't care too much in the past, and only did recently after someone said something to me about them. I realized I drink from them so much, and all of mine have sat in sun for so long on various summits, and been exposed to so much UV radiation, that it might be good to replace them. The steel bottles are nice, but I can see the drawback of them denting.
Society's constraints are stifling! The only way to hike is fully nude!