The Odyssey³ was a VERY bad idea.
Oh, it was capable of decent graphics, and everything, but the unit was badly messed up by the desire to make the machine backwards compatible with the Odyssey². In some cases, they made with very detailed, but non-functioning backgrounds, combined with the same little monochrome block men found in O² games.
Oddly, the games that Magnavox's parent company, North American Philips made for the Colecovision, were exceptional. War Room is fast playing, strategic and a little bit funny, all at the same time. That was not bad for a game based on all-out international nuclear war. Much more fun than the more polished but much more tedious War Games from Coleco.
I had read about the Emerson Arcadia, but never got my mitts on one. That unit was better than the 2600 and Intellivision in graphics, but inferior to Colecovision and the 5200. Emerson tried making a proprietary no frills game player at an aggressive price. They jumped in at the wrong time into a VERY crowded market, and found no room.
The Bally Astrocade was ahead of its time, but had awful marketing and distribution (as did GCE for their excellent Vectrex machine.) They heavily promoted the Z-Grass computer keyboard add on, which was years delayed, and too late to do any good.
I sought out various players, but these were three I never got to use first hand (I did SEE an Emerson Arcadia in the offices of Pumpkin Press/Video Games Magazine.)