The other standout? You probably guessed it, the HD650! I have only heard the HD518, HD598, and HD600 until today. And on all of them I heard the ignominious "veil". They have just lacked a true sense of transparency to my ears, and I just didn't get Sennheisers. Well, I can officially say that I am a Sennheiser believer now, after hearing the HD650 on the Lyr! Wow! Everything I had read about this headphone but not quite believed turned out to be true. It is natural sounding. It does have drop-dead amazing mids. It does not sound veiled. It is a forgiving and easy listen, but without sounding boring! - This especially was a surprise. I had until today believed that a smooth sounding headphone could not also be engaging. Well, the HD650 pulls both off, somehow. And, for me this was very important, the bass slam was great! This headphone manages to be a forgiving, easy listen while having the slam and dynamics to engage on even the aggressive rock and metal I love! I don't even know what to say about that - it's something I have not experienced in any other headphone.
I even got to A/B with the HE-500 briefly (on the Lyr), a headphone that I have more familiarity and experience with. And...well, the HD650 honestly sounds more natural. Am I the only one who thinks planars have a strange soundstage presentation? The HD650's soundstage presentation is great! And the mids? Yeah, no comparison for me. The HD650's mids presentation was much more natural, engaging, and enjoyable than the HE-500's. Now I still appreciate the HE-500 for the many things it does so well! But...the HD650, wow. I am seriously considering getting this headphone.
So yeah, I may be joining the ranks in the near future, HD650 owners! I understand now, forgive me it took this long!