Pentax 645 vs 67 Lenses

I see there is an adapter that will allow me to use 67 lenses on my 645... Is there a strong reason to use 67 lenses? From looking at KEH, maybe the 67 has some faster lenses? More variety?

Any pros, any cons???

There is a soft focus lens for the 67 but not the 645, as well as some interesting lengths that aren't available in 645. also a f2.4 lens which is a little faster than the 645's 75mm f2.8 lens. Also the 67 macro lens is cheaper used than the 645 macro lens..

Pros? Cheaper, more selection and choices.
Cons, the 67 lenses have a slightly longer perspective on the 645. The 67 fisheye _might_ not focus at infinity..

Bighead,
Usually adapters like this were made to allow use of an existing system(67) when a new system(645) was introduced to encourage the purchase of a new "compatible" system.
It's a good thing if you have some 67 lenses already but just a gadget if you don't. Unless you have a special purpose lens in mind. It would be nice if you wanted to use the leaf shutter lenses with flash, but I don't think there's any real speed advantage to the 67 series lenses.

And thats kind of what I was after... Something a little speedier.... I have a TLR for leafshutter / flash combo, so, no real need there.