What I would pick...
The only washer-dryer combo I ever watched operating, was our friend's old big Whirlpool. My aunt & uncle in Buffalo had a Duomatic, but I visited them way after they got rid of it. If I could pick the one I wanted now, it would be either the Duomatic or the 1963 Kenmore like the coppertone one in the ad above(or Whirlpool). The Duomatic spun the fastest, at 560 RPM, as I have a brochure for it here. I never even saw an Easy, SQ or Maytag combo in person. Of all the stores here in NY I used to go to, not one had those machines.