I bought a Johnson resonator about three years ago at Elderly Instruments. It was in the $400 - $500 range as I remember. (I got mine on a $100 discount sale)
So far it's been a pretty good instrument, but I don't play it all the time. The early ones were made in Eastern Europe and then they started coming from China. Johnson also makes regular guitars and banjos - haven't tried any.
At last year's Seattle Folk Life festival I saw more Johnson resonators than any other kind being played by buskers.