I own the FPB 200c, and haven't compared to the other two, but did own the KAV250a just prior. I have to believe that the step from the 250a to the 300 is the huge step, and from the 300 to the 600 minor in comparison. The 10T's like a lot of juice, but the 300 will deliver it, IMO. I'd go for the 300, feel comfortable about the spend, and start buying music again sooner.
Are you considering the 400cx, or at least a 300c? It does seem, given your like of Krell, that an upgrade to CAST connects at some point would be something you'd want to allow for.
Are you considering the 400cx, or at least a 300c? It does seem, given your like of Krell, that an upgrade to CAST connects at some point would be something you'd want to allow for.