As my introduction to wet flies (other than nymphs) came from the North Country Spider tradition, very thin bodies and hackling on the sparse side is what I think of when the P&O, Purple and Snipe etc… are discussed.
Purely a matter of preference of course. But that personal preference is such that I very much like the flies @todoroki34 shows in the last picture, no matter that every single fly that he pictured is an example of tying excellence.
In the latest issue of California Fly Fisher, the editor talks about “fish you remember”. And that over the years, there were maybe only half a dozen that really came to mind. Personally, I think that number is low. One of those “fish I remember”, is a 3 pound bass that took a size 16 P&O that was being used to target sunfish in the local pond one late autumn afternoon. I was using a 7’ Granger bamboo rod at the time. It was indeed memorable, with the fish almost taking me into the backing.