Is the Roon Nuceus device a good streamer?

The short answer is yes.  Have been streaming from a Roon Nucleus to a Chord Qutest for almost a year now.  It replaced a Bluesound Node 2i in my main rig.  From an SQ perspective I'd say that the two pieces were pretty close, but that was before I replaced the stock power supply with a 19v Sbooster Linear Power Supply.   With the better LPS in place, SQ of the Nucleus as Server/Streamer surpassed that of the Node 2i.  Can also note that the Nucleus is cable sensitve, and good USB and ethernet cables here do make a difference.  I'm using a Curious USB Cable and Wireworld Starlight Cat 8 ethernet cable.  Hope this helps.

Although I don't have a Roon Nucleus per se - I use SGC's SonicTransporter i5, I didn't like the sound at all when I connected it directly to my DAC in my headphone rig. The floor noise was much higher, and in general sounded more harsh and fatiguing. I put the Node 2i back in the chain (streamer function only), and it sounds much better. 

Having said that, maybe Roon Nucleus and Qutest combo might fare better in your case. Shouldn't be hard to try it out though.

A Roon Nucleus is an overpriced PC...  Have a look at Intel's NUCs...  Also be aware that even Roon suggests to use an Endpoint along with a Nucleus for the best Signal Quality...  In other words, don't connect a DAC directly to a PC/Nucleus...

Arafiq,
thanks for comment. On paper what u have looks good, sorry for your problems. 
I like the standalone nature of the Roon nucleus.  Desktop connection i use seems fine but don’t like the complexity of linking to a separate room and keeping it on all the time.

i see ssd storage in the future so that adds a lot more. Sucks it don’t come with at least a small amount of song storage.  Use of a Stand alone ext drive is less than ideal.