I have nothing but praise for the old Mac Minis. I've got 11 of them running FCP 6 quite happily and these are old 1.6 core duos with intel gma. I'd expect the new ones to simply fly.

If you're saying there's now no dual CPU upgrade path for the Pro. I'd say buy the tricked out iMac, you could even use your existing screen as a second monitor with it.