I have not tried the Moondrop Aria (and I prefer the faceplate design of that to the Aria 2) but was skeptical about it, especially when the faceplate's paint seems to come off over time. There were mixed reviews about the Aria, and the poor reviews were generally on its "cheap-looking" cable, faceplate's paint issue and filter issue. Other than that, people seemed to enjoy the tuning.
I don't have the Aria to compare the sound with but for $10 more, I do see the improvements done and how the Aria 2 may be more worth it. The carry case, cable and build of the Aria 2 are clearly more high-end. I won't be surprised if anyone chose to get the Aria 2 just for its cable because it does feel like a more superior cable with 2 cable plugs provided. The ear tips provided are average but this isn't a dealbreaker.
I listened to the Aria 2 without much expectations but I was very surprised, and in a very good way. Though soundstage isn't wide, everything else sounded great for my playlist. Resolution, separation of instruments, note weight, "naturalness" of instruments and vocals, I really liked all aspects. It wasn't fatiguing and was rather fun for many upbeat songs. I thought the long nozzles would have caused issues but the earphones were surprisingly comfortable to wear.
Moondrop's patented DD structure? Job well done. Some hybrids with more drivers don't even sound as good.