Apple II sprite boards

Around 1985 or so, a couple of manufacturers developed "sprite boards" for the Apple II series (except the IIc, for obvious reasons) These boards featured a video chip (probably a TMS 9918, same as used in the TI home computer) that allowed for up to 32 sprites to be displayed on the screen. One of these boards may have had a sound chip on it as well. (A veritable TI 99/4 on an Apple card, almost!) Of course, the sprites, and any other graphics from the 9918 could be superimposed over regular Apple graphics, due to the external video input on the 9918. Did anyone ever play with one of these? I recall them being rather expensive, not well supported by third party software makers, and (of course) different brands of sprite card were incompatible with each other.