If you can find a US4 or 4+ used and at a reasonable price that could be a thing. The US5 tho they raised the price 1500 - 2000 and that is what’s offered now US5 & 5pro. (new) there is no US4+
I ordered a V550, yes budget was a consideration but I wanted something that has a touch of organic sound. I felt the Niimbus would lean too neutral and analytical for my tastes - especially considering I run a V281 now. I’m wanting to lean more towards the Niimbus sound, but not ready to dive in to the deep end. The V550 is in between the V281 and Niimbus, leaning closer to the Niimbus. And that is as far as I want to go for now.
Disclaimer: I have not heard the 550 or a Niimbus - just going of some well regarded opinions from those who have.
Edit:
The HeadAmp GS-X MKII was also on my list. It should pair nicely with the Spring 3, from those I know who had Spring 2 and that amp anyway. You headphones will play into the synergy too, so…
i dont want to say the us4+ i tried was dac picky but it did change a lot with dacs and i guess that could be good or bad. recently i found out china is knocking them off and it’s so tempting to try one but i just cant believe they pulled it off as well as the real deal, though from some talk i’ve seen online, some people say they actually upgraded some parts over the original and claim they sound better so idk.
That was my decision maker - a couple unrelated sources both said you won’t want to listen X/Y using your DAC and the MKII (one headphone I have and another I want to addition) So… Plus I’ve enjoyed the 2 vio’s I’ve had/have. Also, Arthur has always been so good to work with … I did a loyalty buy, lol