Does anyone have an opinion about the Audioengine D2?

Really depends on the rest of your system. If you have the A5’s it’s probably gonna be fine. 

Not with this unit.  I have one of their Bluetooth DACs and I am very impressed 

After listening to the output of my PC soundcard distributed across the house for many years I almost bought one to transmit to the HiFi to avoid the cheap coax and cheap card amp.
Instead I spent half as much on my first streamer and was immediately blown away. Still am.
I only use the PC now for ripping and loading the streamers over WiFi.