All I have is die cast figures, and trust me, they are way better than plastic. Heck I prefer die cast over plastic anytime,but in reality I have seen this before where vintage toys have gone down in price due to new release of a better figure in demand... Who knows.
I dont really know. In my experience with model airplanes and weapons, the diecast ones allways had rougher finish than injection in fine detailing. By now, the only metal i have seen that can be close to plastic/resin level of fine detail is machined aluminium, not diecast. I hope hot toys can change my mind.