is anyone using an Aurender streamer with Schiit Yggdrasil?

Yes. I have a friend I have been helping build a system with for several years. We got him a Yggdrasil several years ago… then recently coupled my Aurender N100 (five years old) with it and made comparisons with a different streamer and DAC. The N100 was a much stronger performer in all respects than the Yggdrasil. For instance we compared separately the Aurrender N100 and Yggdrasil with a Linn midlevel ~ $5K each streamer and ~$5K DAC. While swapping the streamers made only a tiny difference,  swapping the Yggdrasil for the Linn was profound, with the Linn performing better in all respects.

So, yes. An old bottom tier Aurrender really shows itself to be an outstanding streamer. Would be a great match… with room for growth by upgrading the DAC.

I can chime in based on owning a Yggdrasil LIM and the Aurrender N200 streamer.  My digital path took me initially from the BlueSound node to adding the Yggy while utilizing the node for streaming.  I then replaced the node completely with the Aurender N200 and the Yggy LIM.  Each step produced noticeable improvement.  So yes, my present combination of the Yggy and N 200 works for me and sounds great.  Plenty of soundstage and detail.  I plan on staying with this combination over the next few years before looking to "upgrade" the Yggy.  I believe the Yggy LIM is solid but that I can eventually improve my overall system with a DAC in the $5K -$6K range. The N200 isn't going anywhere soon.  I haven't had the luxury of a friend nearby like @ghdprentice to assist with both a hardware swap and listening but I would wager he is on the money with his comment on starting with this combination and upgrading the DAC later on.  

Both comments are very useful friends. Thanks for sharing your experience.