I don’t think all of the claims are all valid all at the same time, and certainly not for every person nor every rig.
And a lot will depend on how the SR1a are setup, what they’re being driven with (overall chain is always a factor), what your listening level is (equal loudness contours are worth paying attention to), whether you’re allowing for EQ or just running them raw, how the sit relative to your head (you can adjust this, but head profile will still have an effect, especially if it limits your placement options).
For example, I find the SR1a provide the most obvious, and deep (almost no headphone gives me any actual depth to the stage, but these do), image - significantly more palpable and expansive than either the Abyss or the HD800S - but only if the wings are pretty wide open. Depth increases with how wide they are set, to a point. If you close them down then you lose a lot of this effect and fully-closed-down the HD800S would be better.
Speed, yes, I think that’s broadly true … they’re certainly the fastest sounding headphone I’ve heard (all the way up to the HE1). At least in my chain. A different DAC, amp or pre-amp (when I still had one in the chain) could affect this both actually and perceptually.
I think the bass texture is better than any planar I’ve heard. But, to be able to hear that properly required bringing the bass level up some, otherwise it can get lost due to the reduced natural response. The big boys in the planar realm here, like the Abyss and LCD-4 hit a little harder.
Resolution is ahead of any headphone I have here, or have heard. Not necessarily by much in every case, but consistently the best.
Bear in mind I cannot use identical chains with conventional cans vs. these so that has an effect too.
I’m running a DAVE directly into a Linn 4200 into the SR1a at the moment (no pre-amp). The Utopia, HD800S and Vérité both out of the DAVE -> Phonitor X and DAVE -> headphone chains. Abyss and LCD-4 have to run from the Phonitor X or the Woo WA234 MK2 as DAVE on it’s own doesn’t do them justice.