I have Maxivista version 4.0.11 downloaded in December 2009. It is different from the one downloaded in July 2010. I don’t know if that makes a difference.
The Dec 2009 version lets Visual Studio 2010 run on 2 monitors, but not 3.
The July 2010 version will not let Visual Studio run on 2 monitors– you get constant flashing, disconnect-reconnect cycles (same as trying to take the Dec 2009 version to 3 monitors)
When rolling back, the old installer refused to run (claimed it was outdated) and you had to reset the system clock to get the install to complete.
The demo version is .12, but re-download seems to try to force you to get only the point version you originally bought, which is odd because the site seems to imply that you can get point updates for free within a major version. I’m waiting for my phpBB credentials so I can ask on their support board.