McIntosh Mx151 vs. Krell Foundation vs Arcam AV 860

Thank you all for your input.  I see that Emotiva has come out with a pretty slick pre/pro slated to be available Q1 of 2018.  Anyone can weigh in on this unit vs the Anthem/Arcam based on the specs?

I like emotiva, I had their XMC-1. And Dirac is good room correction software. That being said, the RMC-1 was supposed to be out last year, and Marantz is using the same DSPs in their new pre/pro.  The XMC-1 takes 45 seconds to boot up from off, or you can run it in standby, but it’s a very high power standby (30W).  I’d wait to see what the boot and power situation with the RMC-1 is before you fall in love with it. 

Like mcgal, my experience with Arcam won't be repeated.  I went through two AVR 600's.  One died, both were very buggy.

What is the difference between the Arcam 860 and the Arcam AVR 850?  I am confused?

I've owned a Krell Foundation 4K Ultra HD for about three years and my experience matches @babyseaotter99 .  Truly excellent audio performance.  Lots of inputs and outputs.  Clunky OSD with 1980s feel to it.  I'm using mine with a Panasonic Viera VT60 plasma panel, though,which is 1080p not 4K.  So I'm not suffering from the shortcomings highlighted by @dynguy (yet).  However, Krell just began offering an HDMI-switcher unit that works in tandem with the Foundation and addresses the shortcomings.  This two-box approach is similar to what Meridian did with their G-series processors and HD621 switcher.  I like the Foundation so much that I might just buy the new Krell switcher in anticipation of going 4K on the panel some day.  Though, to be honest, I hope my VT60 never dies.