I can certainly recommend the Aune, has dac/amp, usb/coaxial digital inputs and analogue line in/out, good quality components and overall is a very nice and robust piece of kit, it's about £110 off ebay for the MK2 'special edition'.
Tweaks wise, run it with a 15v regulated DC supply, it's plainly better than the wallwart it comes with, and the opamps inside are easily changed if you want to (they are in sockets), though the ones it comes with are actually well chosen and sound great.