Yes, I have all three, they've been burning in since Monday
It is a nice setup... they are all still opening up, but even from the start I would never call the sound 'bright'. Going from the E17 to the Soloist SL, the main differences were a bit sharper imaging, a bit better dynamic response, a fuller sound... basically everything is a bit better, appreciably. Nothing is super dramatic, you have to listen for awhile to really notice all the improvements. The greatest aspect is how the setup makes you feel 'in the music', and not just feeling that it's presented to you in a sort of virtual box. And all this is mainly without any significant burn in, so it's all good stuff from here.
I have had the soloist SL on low gain majoritarily, and have had ample volume.
The upsampling filters on the Concero are also a nice touch.
The really dramatic moment came when I listen to a song as 128 mp3 on my phone with cheap IEM's and then the same song in FLAC with the rig. Wow... at that moment, it's all worthwhile. I truly look forward to going home and listening to music now, which is unusual for me. So much more emotional response to listening sessions, it's more engaging.