very nice!

I really like that guy in full plate...very nice figure. I would add reflections on armour but maybe I'd use a light metal colour instead of white. And myabe I'd use a glossy varnish too on a black armour.
I have to admit I definetly prefer to paint plastics minis. The painture is more reliable, it's easier to scratch a metal mini than a plastic one. And plastic is so funny to convert!

BTW when you paint plastics I think it's very important to use a good primer for a better grip. I use gw skullwhite and I think is one of the best for plastics.