For future reference, a video amp is not needed with a Betson (Kortek) CGA monitor. ?Fired this up last night and the picture is...spectacular.
In case anyone is deciding between an arcade monitor and TV with S-video, the area I noticed the most difference between the two (aside from the games were output in their native resolution) was the color purity. ?While old video card--ATI 9200 series-- produced a very good (and perfectly playable) NTSC picture, the difference is noticable when compared side-by-side. ?I'm happy with the upgrade...
Cheers again to Ultimarc for a great product in ArcadeVGA.
(The color balance is off on the picture below only because of the digital camera)