Yes, I have the Meze ADVAR's and the DX320 and it's a great combination. Regardless if you use the stock amp or get the amp13 card although guitar's on the AMP13 is just amazing, especially emotional effect.
With that said, the only other DAP I e owned was the FiiO M11 Plus. I wasn't particularly impressed with it. More digital, a bit brighter. Based on posts here I decided to get the DX320 as I had 2 weeks left to return the FiiO. The FiiO went back the next day and while obviously a huge price difference it was close to twice as good for MY personal tastes. More analogue, yet very detailed and I honestly feel asleep once while listening. Some of that is because of how lightweight and comfortable the ADVAR's are though.
I honestly don't think you would regret the purchase. The difference was night an day vs the M11. Mid bass was way batter and tighter on the drums, more layered, easy to pick up each instrument, nothing muddled together. Slightly better deep bass but the ADVAR's do not have the best lower bass frequencies because of the design which is fine for the music I listen to.
If you like the ADVAR's, the DX320 will make them better, that I can guarantee.