Dreamcast VGA question

[bombatomba]

A number of years ago I purchased a third party Dreamcast VGA connector from Gamestop.  I've used it regularly over the years and never had any problems.  Then the other day I was in a discussion with a friend and he mentioned that he was trying to playing through Silver again, but on his older TV instead of his 22" LCD.  When I asked why, he explained that his VGA (a first party model) will only work on games made for VGA.  He also suggested that my VGA didn't actually work since I could play any game, regardless of compatibility, through the VGA switch.  

Now I did have some time to test this using my 20" Gateway monitor (which has multiple input capability) and there is a significant difference in Shenmue between composite and VGA, but I've never seen a first-party VGA in action.  So my question to all of you is this: Has any of you made this comparison before?  Does the official VGA really not display all games in VGA?

[Lendorien]

AFAIK, most dreamcast games are VGA compatible and almost all of the third party VGA boxes have the same guts as the Sega one.

The reason you haven't had any issues is probably because you haven't actually run across one of the few non-compatible games.  I don't claim to be an expert tho.