I disagree with Ralph, and believe the qualitative difference from 6x6 to 4x5 is even greater than from 35mm to MF; but it really all depends on what you're trying to accomplish, your skill level, and
how big you need to enlarge things. Working with a view camera is very different discipline than with
regular cameras. There will be a distinct learning curve. Even modest movements can dramatically increase versatility - so once you have them and know how to use them, there will be a whole new
range of opportunities (speed won't be one of them). Most of the old hand-holdable "technical" 4x5's
have some movements built-in. But working without a tripod ain't particularly easy.