I just swapped out my tubes in my Millet for some 12FM6s (Tung Sols) and the SQ with the Devilsound is perfect; I also found that pairing a SS amp with a NOS dac sounds amazing as well! (I tested out an EC/SS with the Devilsound - it's incredible!)
I found the RS-1s and the HF-2s to be very similar. I listened to both of them out of a MAD amp; but the HF-2s are more forward sounding, with better bass, and smoother highs. I love mine
I have a Devilsound NOS dac hooked up to a Mac (hey, that rhymed). I'm using a Millet Hybrid amp with it and listening with HF-2s. My ONLY complaint is the highs are a tad grating; I've broken in the HF-2s for many hours, and I'm thinking it may be the dac. Time to EQ a bit more. Other than that, I'm really happy with this setup
The ESW10s are an even better can than the 9s. Better detail, better highs, and they sound more open. (for a closed can)
Too bad they cost a helluva lot more!