Rsjm:
Contrary to the popular belief, Apogees hybrid need a lot of power, just to make the woofer keep up to the ribbon speed. I have owned Apogee Centaur Majors, which were my references speakers for eight years before I upgraded to all ribbon (and I was extremely happy). I drove them with tubes at the top and a very powerful SS amp at the bottom. Only with a powerful SS amp at bass were they able to generate good bass.
I suppose the Slants are no different even thought I have myself been looking for a pair of Slant 8s for quite some time. So unless you use a good powerful tube amp like the Jadis 200, 500, TRL, or CAT, you probably will not be able to get the max out of them.
Regarding the Brystons, I tried them on a long time ago. They clipped on the Majors.
Class: Good midrange but soft bass.
McIntosh: I owned 502, the monoblocks. I did not like them.
I have to agree with Satch and it seems like we have the same opinion. I also agree that the new Pass Lab amp should be a good candidate. In fact, after I had purchased the McIntosh, I had the opportunity to directly compare the Pass 350.5 with the McIntosh and there was just no comparison. I told myself that I had made a big mistake. However, I sold the McIntosh soon and moved on to TRL and thus did not have too look back at the Pass.
But give it a listen to all of these if you can. Who knows what might work for you. But please report it back to share your findings. Thanks.