You could also look at the Pompanette (Bowmar) Grey series. They are heavy duty plastic. Again, clearly not as good as cast aluminum or cast stainless steel. But, unclear to me which is better high-grade plastic or extruded aluminum.
My boat had plastic ports that were either original to 1981 or very early add ons. I just replaced them in 2019 -- 38 years later. And, it wasn't because the plastic went bad. It was death by a thousand little things -- metal hardware was rusted or broken, seals were bad, they needed to be rebedded, and there weren't spare parts available. So, once I pulled them to rebed, unable to get spare parts, rather than make new ones, I just replaced them with Lewmars. It isn't clear to me the Lewmars will last 38 years. I just don't know.
But, I'd put the Grey Series at the top end of plastic.