Is Roon Nucleus the best choice for Roon Core and as server?

I am in the market for a Roon Core and a server for my stored music Including high res, cd quality and some old MP3 I cannot find elsewhere. Some servers I have looked at suggest keeping the Roon Core separate due to the heavy volume of metadata. As I don’t have that much stored music, I would prefer to do these two functions in one unit and spend more on the streamer and the DAC. Is Nucleus by Roon the best choice? I see an RS9 being advertised but can’t find any information in it.
Hard to say what's best but the Nucleus would work.  How many GB's of music do you have and what's your budget? 
I have been using a Roon Nucleus as a server/streamer since November and am very happy with it. It has a bay where you can install an SSD or HDD.  I'd go with an SSD.  You can also just hook up an external storage device via USB.  Connect it via ethernet cable to your network and connect up your DAC of choice via USB (or for that matter via HDMI should you have that option) and away you go.  I have mine hooked up to a Chord Qutest via Curious USB Cable and am very happy with that arrangement.
Not a large collection of stored music.  Where the album is available on Qobuz, I am usually pleased to stream it.   Prefer to keep this purchase in the neighborhood of the Nucleus to spend more, as I said, on the other components.  Thanks for these suggestions, I will check them out,
If you can follow instructions you can assemble your own dedicated ROCK server. Mine cost about $600 not counting the price of Roon. The OS is free.

If you use Roons OS you don’t need a streamer just an endpoint. Some DACs can be endpoints if the DAC you like isn’t all you need is a Roon bridge.

In my system I have a NUC running ROCK connected by ethernet in my home office. My ripped music files are on a drive connected to the NUC. In my listening room I have a raspberry pi4 running Ropiee which is a bridge connected by USB to my DAC. I control it with Roon app on tablet.
I built a Roon Rock server referenced to the top spec Roon details on their webpage;
Intel i7 8th Gen NUC
256GB SSD for the free "ROCK" OS
1TB SSD for content;
Cost about $750 all in; 

It's my understanding the above build is identical (save the awesome fanless CNC case of Nucleus) to the Nucleus +;

Best audio and functional performance I have heard yet from Roon. Boots in less than 3 seconds; Stable 24/7; Zero glitches, hangs, snags, pops, etc;
I messed around with Roon running in several popular platforms over a long period of time; I spent a lot of money experimenting with Roon and these various hardware bits; It was a mixture of fun and frustration, but the first hand experience was worth it; 
I highly recommend to anyone--build a Rock based Roon server; Go for the top spec; It's worth every penny!!

I have a v1 Roon Nucleus (not the +).  It was a notable set-up from using a MacBook Pro (look at my posts in other threads for more details).  Music in both cases was a 2TB Samsung T5 external USB drive.  Now i am getting close to 2TB of music, I purchased a Samsung 860 QVO SSD 4TB which I have yet to install.

It is a turnkey, easy solution.  If you want to build something, I think you can make something comparable for less, I was just more interested in saving time and hassle.

I am using a Schiit Yggy DAC, or KEF LS50w's, both of which are seen as Roon endpoints.
I LOVED the Roon software but was having stability issues running from my PC. I have built my own amps and I started a speaker company and was moving into the audio business.

I never thought about building my own server like the Rock above. I reached out to Roon for a discounted unit to use at AXPONA and I was talked into becoming a dealer and running a Nucleus+.

The only value to the Nucleus+ over the Nucleus is processing power and two things make a difference. The Nucleus+ is required if you want to run a DSP on DSD rather than on PCM, or if you have more than 120K tracks in a library.

I don’t know if it is the best available. I hear amazing things about units from Antipodes and Rockna but it is definitely the best in its price range. 
Hi guys, i’m also looking at different alternatives for Qobuz streaming only and perhaps little local storage.Would a Roon Rock server be up to the task in a 180K reference level system or should i look at more expensive streamers like Innuos or Antipodes ?Right now i’m using a dedicated fanless NUC with SOTM external USB reclocking and Daphile for Qobuz streaming in my headphone rig.
Building your own Roon ROCK server is a great way to save some money and still get an top-notch product. My configuration used the following parts:

Intel NUC8i7BEH (i7 gen8): $659
Crucial 8GB DDR4 x2: $58
Transcend 128GB PCIe SSD: $29
Samsung 860 1TB SSD: $130
Samsung 128GB Thumb Drive for backups: $18
Akasa Turing Fanless case: $175
ZeroZone 100VA 19V Linear PS: $175

Total: $1199

This is the same CPU, twice the RAM (probably not necessary), twice the boot/database drive size (allows much larger library), Linear power supply (the Nucleus+ comes with a SMPS), and 1TB library storage (not included with the Nucleas+) at half the price.

The NUC comes with a SMPS, so you can use that if you don't want to upgrade to a LPS. 

It did take about an hour to set up the NUC with ROCK, and another hour to install the NUC in the Akasa case, but it's relatively straight-forward and has worked great since I built it in January. 

The NUC is pretty quiet in its standard case, so even if you want it in your listening room, you might be satisfied without the fanless case which saves some money and time.
@jaytor  Thanks for your input, my NUC is also in a fanless Akasa case very easy to mount indeed.I will do the same with an I7 NUC and add a linear PSU to the NUC.Install Roon Rock and get Roon membership.This NUC will be connected to my router via ethernet and from router to dual quad Paul Pang switchs and towards Totaldac d1-Twelve mk2 DAC.This configuration should be at the level of a top notch CD transport.