The SR-5s are amazing for the price they go for these days, but I'm going to have to agree with you that they aren't top tier. As I've said the Beyerdynamic T90 was more detailed.(the SR5 and HE6 came out in a tie but I think my amplifier was bottle-necking both of them) Where the STAX really shines is with timbre, sparkle, and soundstage. Listening to the HD700 though let me know that the STAX are too lightweight in sound(somewhat basslight but less so than the HE6) Basically the STAX do some things quite well, better than most sub $1000 headphones but also do some things poorer than even $200 headphones. You have to really like what they're giving to you. I don't hold the belief that Orthos nor Electrostatics are superior technology to dynamics despite what seems to be the growing consensus. They are far more polarizing and dare I say niche technologies. I think I'm going to be one of the few who returns from electrostatics to dynamic. The T90 and HD700 got me close to what I was looking for so I have high hopes for the ED12(and if not this maybe I'll move on to the T1 or a AT woodie).
When you say that the Ultrasone are different, what do you mean exactly? I'm looking for something 'different' but I do still value a neutral sound. I found the HD700 too 'fun' but I wasn't too turned off by the Beyer's warmth(rather by the too forward soundstaging). What I do notice is that Ultrasone seems to be targeting these at Stax users as they've been using words like 'Airy' and 'Ethereal' in product descriptions.