Which amplifier

@mfdamon Though I'm sure both are outstanding integrated amplifiers neither in my opinion are an appropriate match for a Cornwall. You might be better served, have better sound quality and save a great deal of money by looking at something along the lines of a Luxman SQ-N150 integrated for around $3500 new https://luxmanamerica.com/product/sq-n150-integrated-amplifier/  plus have all the benefits of a factory warranty, dealer support as well as the reliability you’d get from the McIntosh and the Accuphase. If your budget can stretch, this might be even better https://luxmanamerica.com/product/lx-380/. This is what I’m currently using with my Cornwall IVs and I’m completely in love!

Of the two, I would go for the McIntosh.

Tough Choice. Two really great amps. I think both would drive those speakers with ease. I think I’d pick the Mac. Luxman is a solid choice as well. The build quality on the Luxman and Accuphase would be slightly better as Japan tends to do this exceptionally well. I have not heard the amps with your speakers….

I had a pair of Cornwalls driven with a Coda CSIB. It was a great tonal combination, big soundstage, exciting but not bright. I felt the Cornwalls wanted a bit of power. I demoed them with the small Luxman tube amp and just didn't feel that combo. I also used an Audio Note amp but the Coda was on top IMO.

Never heard the Accuphase, maybe look into damping factor combo for these speakers.

For resale, guessing the McIntosh.  The McIntosh is a great down the middle of the fairway amp.  I have one and listened to many.  Not exciting or toe curling.  Very little deviation in dynamics through the volumes.  Nice and flat. 

Haven't listened to the Accuphase so don't know.

Hate to go there but what about neither?  Such wonderful efficient speakers that are going to have more power than they need, imho.  That is unless you are just looking from some greater decibels. 

Have you thought about a low wattage S.E.T. tube or something from First Watt?  Audiophiliac does some reviews of the Cornwalls paired with various things and nice results from Decware.  

Good luck and please let post what you end up with and how it sounds.  Either will be great.