Roon vs Bluesound

Apples and oranges for the most part.  Roon is a _software_ solution for managing your music that is dependent on hardware (a Roon "core" and Roon "endpoints").

Bluesound is hardware for streaming, ripping, distributing your music that includes some decent hardware but can also serve as a Roon endpoint.

They are complementary products.  If you get Roon, you're going to have to have at least one endpoint.  It could be a BlueSound device or dozens of other devices.  There's a lot of Roon ready gear out now.

I've been very happy with my BlueSound Node 2 as a music streamer for Tidal, Spotify, etc. and for accessing the music collection on my network.  I've been considering Roon, but am having a hard time justifying paying for software to replace the free interface the Node 2 has which works quite well.

If just using them with digital outs, identical.

If they sounded any different with digital outs, your DAC sucks, which surely isn’t the case with yours.

Marantz looks to have the best pre-outs for processor use, Denon is still OK (get an X3400 and just use the pre-outs), but Yamaha is not good, can’t even do 2Vrms and not as clean. You want Audyssey for your system, even if just for the subwoofer (you can have it correct everything or bypass the mains). All the Denon/Marantz models of the same range use the same AKM DACs, so the digital aspect for surround sound will be the same. For the analog inputs from your DAC, the Marantz may be cleaner though.

I would also recommend demoing a high end SVS subwoofer (free returns), and if you like it more than your REL, get a high end Rythmik or PSA subwoofer (they charge for rerun shipping, but that helps keep the prices low).

No need to go crazy for an amp for surrounds, any Emotiva would work.

Thanks everyone for the help! Lots to think about!