THERE WERE A NUMBER OF TYPEWRITERS WHICH EITHER DELIBERATELY INCLUDED THEMSELVES IN THE REVOLUTION OF VISIBLE TYPEWRITERS, OR ELSE ADVERTISED THEMSELVES AS SUCH, BUT WHICH WHEN COMPARED TO THE OTHER TOP-SELLING MACHINES OF THE DAY WERE QUITE UNCONVENTIONAL.
The machine probably most familiar in this group is the OLIVER, which owes its unconventional nature to the fact that its inventor, Reverend Thomas Oliver, knew of the existence of mechanical writing machines but had not operated one himself before launching his venture to create one.  This approach, while seemingly slightly unlikely and in fact doomed when one considers the competitive environment, led Rev. Oliver down the correct path; by the time the turn of the century arrived, the Oliver's bugs had all been worked out and it was already establishing itself a fantastic reputation as a rugged and reliable machine.  It continued to be a competitive threat for another two decades, through successive models, even though it never dispensed (in US production) with its double-shift three bank keyboard.
The Emerson did have a few things in common with the Oliver -- for example, it was produced (for the most part) in the same city, and had a very similar three-bank double-shift keyboard.  One advantage it had over the Oliver was that much more of the writing line was visible, with the machine being so open in front and having a much more conventional carriage mounting.  The wholly unconventional (and unduplicated) arrangement of double-banked swinging, or hinged, type bars allowed high visibility and easy type-face cleaning, and the shift was easier to operate than the Oliver's since the type-bars were raised or lowered instead of the carriage being moved. 

The biggest difference:  the Emerson was never a good design and was a complete and dismal failure.
The Blickensderfer Manufacturing Company, Stamford, Connecticut did in fact advertise its type-wheel machines as being "visible typewriters."  While this may be of some question when compared with machines like the Underwood or the Monarch, the Blickensderfers certainly were much more "visible" than any of the old upstrike standard machines.  These machines are quite well covered in the available literature, but since the advertising was altered to deliberately include this design aspect, we must then include them somewhere on this site.
February 1906 advertisement for Blickensderfer.  Note the description as "NEW 1906 MODEL  VISIBLE WRITING."    Ad from Davis Family Collection.