I just got mine last week (finally!) They've been on back order from Alpinstars forever!!!
Anyway, to (kinda) answer your question, yes they are comfy, very comfy.
I only wore the regular SMX boots for a half hour(track time), so take my comparo w/ a grain of salt.
The new Plus' are more comfy and stiffer than the reg SMX, and fit (at least me) a hell of a lot better.
Hope that helps.