I haven't seen a lot of info about this here before, and I had never thought about buying a polymer lower, since forged aluminum lowers have historically been plentiful and cheap.
However, I've noticed that polymer lowers are now available for around $120 - $150, which is considerably less than aluminum lowers are selling for. That's when it occurred to me that polymer frame handguns have been proved to be extremely reliable, so maybe a polymer AR-15 lower is worthy of consideration, at least while aluminum lowers are selling for outrageous prices. And if the prices of aluminum lowers come back down from the stratosphere, you could always buy one and swap it out, and in the meantime you would have had a working rifle.
Do you have experience with a polymer lower? Are they worth buying, at least as a temporary measure?