Streamer Recommendation

1500 approx used budget

I would add Bricasti to your list.  Might be able to find a used one near your target budget.  All three, Lumin, Aurender and Bracasti are great streamers just depends if you want a propriatary meta data manager, made in US, etc..  I use Roon so Bricasti works great.  Also consider a dedicated music server.  You can build your own or go as high as you want on price.  I've been happy with my Small Green Computer i5 with a 4 TB SSD.  

Used BDP-2 goes for around $1.5K.  I have seen used BDP-2 with the upgraded board for $1.7K.  Later you could set up Roon and use the BDP as an endpoint. 

I am a big fan of Aurender. I have tried a lot of approaches, including a Auralic Aries G2 and have been really impressed with Aurender. I own two… see my systems under my user ID. They arguably make the best high end streamer… used  most frequently in audio shows and that is the only component they make. I have found each level up, is well worth the incremental cost and their Conductor app is highly reviewed. 

“Looking at Lumin/ Aurender”

There are couple of Lumin D2 or U1 listed on US Audio Mart and here if you’re flexible with your budget. I am afraid, you’re not going to find a Aurender anywhere close to your budget with BNC output. You would need to step up to a used Aurender N10 for BNC connectivity.

The app interface is a critical piece of streaming experience so choose wisely. The Lumin app is pretty decent but Aurender’s conductor app is the best app after Roon. It’s stable, well laid out and uncluttered in direct contrast with Roon.

Good luck!