You will not notice any cycling performance difference between stiff roadie shoes and cleats and stiff mtn shoes and spd. If you ever can, you will be experienced and skilled enough to know what works best for you. I don't see how roadie shoes with cleat covers can even be compared to the convenience of recessed mtb spd walking. But since life is an adventure to be experienced, not read about, try them both! Its only money.

edit: and also pick up some band-aids. Everyone tips over eventually while still clipped in.