I have had this for almost a month now. I think it was probably broken in by the second weekend. Since then, I have not heard any new changes in its character. To me, this has a lot of the qualities that Naim is known for. It has that drive and forward momentum and the ability to get your feet tapping. Tonally, it is not as dry and threadbare as Naim (at least from what I remember of Naim), but it also does not have quite the tonality of my Croft integrated. The Croft uses a tube for the driver portion of the Mosfet amp, so that may be where that nice tone comes from. The Croft is also tonally richer than the Aria at the lower volumes that I mostly listen at. At moderate volumes, the Aria comes into its own though - a wonderful balance of tonality and PRaT. I found that the forward drive of the Aria was great for classical music. It somehow imbued it with the feel of a live performance. For other types of music, it was a mixed bag. Highly compressed stuff sounded pretty bad, a little worse than I normally hear it. Stuff that was nicely recorded was superbly balanced and just a joy to listen to. Kind of what you would expect of good/bad recordings, but I felt it was a bit more extreme on either end.
I wish I still had my Harbeth P3ESRs as I think this would be an ideal amp for those speakers, and I am guessing better still with a pair of Harbeth C7s. I am currently running a pair of Audience The One speakers, 3 inch single driver speakers, along with a REL T2 sub. I think my dis-satisfaction with low level listening may be due to this particular combination of speakers and amp. I actually think tube electronics would be best for this, but I didn't want to mess around with an all tube setup - I wanted something I could leave on 24/7. I also kind of think that a full range speaker would work better with the Aria than a "satellite" speaker and a powered sub.
I also tried the Aria out on a 1957 Ampex console that I inherited from my dad. The electronics are gone, but the speakers still work. They are 93db efficient two way speakers with a bullet tweeter and a "full range" woofer. They are badly colored (tubby midbass), but tonally juicy, and have a way of just letting go of the notes. The Aria, partnered with these, was great. The Aria had the control necessary to keep a lot of the tubbiness at bay and let the tonally rich nature of these speakers come thru.
I am hopefully retiring next year and this was supposed to be my final amp. That may very well be - I am happy with it. Only time will tell though. And time has an unfortunate way of f**king with my head