Starting my winter climbing career in the late 80s I date from the time when plastics were in general use, and lots of people used and liked them because, as long as they fitted, they were good tools for the job.
They were displaced from a lot of technical climbing by developments in composite leather boots which became lighter and (AIUI) gave better feel with the same rigidity, but if you're not doing technical stuff (i.e., high grades) then they still make excellent sense because they're very warm and very tough, and if they're the right ones very comfortable.
To reinforce GOF's point, fit is vital, be the boots plastic, leather or whatever. The original Koflach Ultras and their successors (Viva Softs, Scarpa Vegas, Asolo AFS 101s etc.) were widely joked to break your feet in to them, but that was just a case of the wrong boots. Mine are Scarpa Vegas (the original shocking pink model!) and I could spend all day in them happily as I have Scarpa shaped feet. I can spend the day in my plastic Scarpa ski touring boots too, including plenty of walking: if they fit they should be fine as long as you relaise that you only need to lace the outer tightly for technical stuff. They still make Vegas after more than 20 years so I doubt they're that bad!
I'd be inclined to go to the likes of Peglers, have them line up all the really toasty boots and select according to fit, rather than if they're plastic or leather or whatever.
Pete.
