Dn't get an early one. In the place I worked in the late 70s we had 3 in order to keep 2 in circulation. Can't remember what the probems were: I almost never used the thing, though I did try some street photography with it. It was... OK.
Street photography with a Linhof Tech 70 is quite fun, and it's a bigger '6x7' too (72mm long - I seem to recall that the Pentax is 68mm).