The Apple Color Plus worked for me back in the early 90s. I used to use it on my IIci's built-in video until I got a video card for it.
However, the ACP is subject to a fuse blowing problem. A lot of them had it. And mine eventually died by blooming the screen to either super bright or super contrasted. There was probably one bad component in there that needed fixing, but by that time we were ready to switch to LCDs. I still have a 14" viewsonic around here that will work with it though.