Why does it have to be so hard?
I have a Douglas SPR with CLE chamber and matching bolt on the way.

I'm thinking heavy barrel with a heavy SPR/M2 suppressor, I need a good solid upper, and so on...

I've been digging, and finding lots of opinions on billet uppers and monolithic uppers and so on.

I found a discussion where a guy claimed Vltor MUR was one of 3 brands he had used that did not require truing of barrel face, so got to looking at the Vltor site and looking at their Polylithic uppers.
the MUR:


The VIS fusion


Not a fan of keymod, but I'm not planning on bolting anything on it anyway.
I just need something that will handle the weight on a rail mounted bi-pod without flexing.

And for some reason 15" seems to be the one everyone wants to get rid of, and the size I want for an 18" rifle length build, so it's a very cost effective upper/rail combo.

I would not base the decision on cost over function, but if the function is as good as any, might as well save a couple hundred.

Others that were mentioned were San Tan and Cross Machine Tool

If I get a non-monolithic upper, I'll probably get an SLR rail, but I'll take advice on that too.
All I have is a barrel on the way, and a bootleg adjustable BCG to put in it. Aside from that, all options are on the table.

The problem is there are just too many people making AR uppers, and not enough users with diverse experience.
Many of us haven't built with any diversity to say this is good, this is better, this is bad,....

Kind of hoping not  to have to by a facing jig, but will if I need to.

How cheap have you found it?  Midway has it for $364, but for that money I can find a rail and upper that's more my taste.

There's not much info out there on them.

I'm a big fan of those MUR upper receivers.

I have one of the older quadrail VIS receiver/handguards.  
It's a bit heavy, but a nice piece of equipment.

MUR is a very nice upper Ive used two. Next time Id probably go without the FA though.

I have a Noveske 18" SPR upper that Noveske built using the Vltor MUR.  It is a beast.  Very strong.  Highly recommend it for a precision AR upper, particularly one with a medium/heavy-weight barrel.

Cannot speak to the VIS Fusion; I've never owned one.

$275
https://www.rogtac.com/vltor-vis-km-fusion-polylithic-upper-handguard-with-keymod-15/

If I get the MUR, I will also.

The MUR has been used for precision builds for awhile. I’ve had good luck with BCM uppers, which are just a tad undersized for a tight fit. I don’t know if it matters or not, but the end result works great, and it gives me the warm and fuzzies.