I'll throw in my 2 cents for a kodak as well. The carousel projectors are quite common, so you could find one (working too) at a garage sale, craigslist, or a thrift store/consignment shop.
A guy down the street from me has one he was looking to essentially give away, with a few trays and all. Some appear in my local classefieds, but never sell (as people forget they have lost all value.)
I personally use a Keystone 770, have enjoyed it enough to want to replace it. It uses carousel type trays, but SIDEWAYS, and the automatic advance is push the button top remove the slide and advance the tray, then manually push the slide lever back in to load the next slide.
If you want the best of the best of the best, then an absolute top of the line Rollei, Leica or Hasselblad projector will be what you want.
If you shoot medium format and want a projector that can handle that, then all I know of is Mamiya apparently makes a slide projector, and there is Götschmann as well.
But, seriously, Carousel is very good for what they usually cost.