I had a Sears Freespirit. It was fine around town and back and forth to school in the mid-late 60's. Then my Boy Scout troop went on a couple of "bike hikes" and there were some hills involved. I wound up walking up while my buddies with the derailleur bikes rode right up like nobody's business. At that point I was done with the 3 speed and bugged my parents for couple of years until I got my first 10 speed and I haven't looked back. I don't miss it one iota.
Jon