Re: Cost of AMD CPU In General
Until recently AMD haven't been comparable except at the low end - their APU offerings are ok because the standard of bundled GPU is better (for desktops) than the Intel alternative. They also do some interesting embedded options.
With Ryzen, at the high end they're not quite as good as Intel, but a lot cheaper. If you don't need the absolute fastest single threaded performance they're a decent deal.
They haven't kept up with virtualisation enhancements like Intel, though, aside from the new encrypted memory options, which is a pity at the server end.
For a low end box, I'd have no issue using AMD. For a reasonably high end desktop that's mostly concerned with running lots of processes, but also needs to be quite fast, I'd also consider AMD. For an all out gaming box I'd go Intel, and for virtualisation I'd look at a Xeon.
For an embedded firewall I'm looking at an Alix APU2. AMD Jaguar core, fanless, decent encryption support on chip.