Being a huge Sega fan, I was disappointed when I discovered that the supposed Sega Vision is primarily a PMP. Sega of America stated that "the Sega Vision is a real device, but is not intended to be a re-entry into the hardware market and is not designed to compete with Sony or Nintendo." Sega continued to state that it is primarily designed as an MP4 player (which isn't surprising considering the layout).
Source: http://www.rpgsite.net/news/281.html
They also stated that it's not actually designed by Sega but a cheap third-party in China. I really hope that Sega is able to make it back into the hardware business someday. (there recent game lineup seems to be of a higher quality lately; so maybe they will be able to afford it in the near future?)
According to Sega of America this is indeed a real device. Unfortunately it is made by a cheap third-rate company in China and is primarily geared as a MP4 player (which isn't surprising at all considering the layout). This is a devastating blow as a Sega fan, but perhaps Sega's latest line-up will pull them out of this tailspin.