I bought an Ericofon on ebay a few years ago. I thought it would be useful in our den and would also serve as a conversation piece in more ways than one. It turned out to have an issue with the switch contacts related to the dial and switch hook, and because it was so flimsy in comparison to a WECo phone, parts broke when I tried to repair it. I declared it junk, and decided that an Ericofon wasn't worth owning.
While the design was interesting, there had to be a learning curve regarding how to set down the phone if stepping away for a moment, since standing it on end would terminate the call.