the new ones as of a few years ago are real sturdy, they are as good in my opinion, the only thing about them I am starting to learn is when you are grafting and raising queens, bee will draw out wax longer than they will draw plastic, One advantage to using pierco is if they make burr comb you only have to scrap it off...
example: from what i have seen with plastic they draw only when there is a good flow or just when you are feeding heavy before the flow and you have a good quantity of bee's during that flow or feeding, the only time I see them not drawing wax foundation is when their in a dearth, like I said above I am just starting grafting and need allot of frames and cell's being drawn out, I am using wood frames and small cell starter strips (small cell foundation I cut about 2 inches deep that was giving to me from a good friend) so my other hives can get these going for my nuc's that i'm going to put these queen cells in, now I get small bee's with the pierco and I like the plastic but it the drawing out I don't like compared to the wax.... but this is just what I have seen... but if I was just going to keep a few hive and not get into the queen rearing thing I would use the pierco, hope this helps...