McIntosh Mx151 vs. Krell Foundation vs Arcam AV 860

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.

@srestivo the Krell 4k will pass 4k signals. So even if you do upgrade to a 4K TV it will handle the signals. The switcher allows passing 4k HDR and HDMI 2.0. I guess most newer TVs are 4k HDR hence the need for the switcher. $1,000 for an HDMI switch is pretty steep though, but I guess it's Krell so it's gonna be pricey.

I agree - if I ever upgrade to a 4k HDR TV I will likely get that switcher rather than go to a new processor, but my Pioneer plasma is going strong after 12 years (knock on wood!)

"We have had many requests for an add on to the Foundation to support HDR and HDMI2.0b, hence, the Krell HDMI 4K HDR Switcher with specs shown below. It hooks into your RS 232 port via an adapter, supplied with the unit."