I like the Channel Master CM7000, as it has S-video, and I figured out how to turn off the chroma (remove cap CV6, and connect a 0.1uF cap to pin 4 of chip UV1 and the other end of the cap to ground, or the center leg of a SPDT switch, with one end of the switch to ground, and the other to the chroma signal to make it color or B&W switchable) before it hits its TV modulator.
Good for feeding B&W TV sets, especially the late 40's early 50's sets.