There have been many comparisons of the Expanse to the Cladera and having owned both- I want to put in my two cents.
First and foremost- from a technical standpoint; ther is nothong to talk about. The Expanse is so much more resolute, noticably better seperation, detail, so much less distortion. Ther Caldera is much more colored. The Caldera is indeed a pleasant sounding headphone, with rerasonably good technicalities, but is still more focused on coloration rather than technical accuracy. In fact, I can say with confidence that the Expanse is on of the most technically superior headphones I ever heard when properly amped, and I have owned the phi TC, and many of the Stax electrostats, LCD-5, and Susvara. The Expanse has excellent bite and transient attack as well- way above the Cladera.
Now, one should not think the Expanse is so technical that it is not enjoyable. It is IMHO immensely enjoyable. The Cladera is as well, but it is doing so from a perspective of coloration- and it does a very nice job; smooth and full sounding with respectable technical performance.
Regarding soundstage- there have been many comments as to the Expanse soundstage being pretty small for an open headphone. Now, I do have a CFA-3 which is known as perhaps the premire SS headphone amplifier for soundstage, but in my system, the soundstage of the expanse is superb. Not the biggest ever heard- for sure, but absolutely excellent.
WIth proper amplification, this headphone is one of the very best I ever heard. So so well belanced in every area. The tuning is to my tastes as close to perfect as possible, and all the frequencies are so well balanced. Just magnificent.
Regarding Susvara, it is so soft with such a lack of bite, and punch- I never understood how anyone liked it. I guess for classical or Jazz- perhaps, but it just lacks the dynamic slam and bold punch of the Expanse... and for that matter even the Cladera. It is way to limp for rock and roll listeners.
Regarding the Phi TC, it exceeds the Expanse in soundstage and bass, but it has severe illness in the midrange area which the Expanse does not suffer from. The Expanse is similarly explosive to the the TC IMHO, but more balanced. Part of getting that balanced tuning and tone involves having a more normal size soundstage and more moderate bass quantity; although in quality- it is as tight and puchy as anything I ever heard.
LCD-5 has similar technical performance to the Expanse- one of the very best in this area- but the tuning is terribly off. Expanse is what LCD-5 should have been from a big company that has the resources do get the job done right. The 4z remains IMHO the best Audeze in the lineup. It is only slightly behind the Expanse and LCD-5 in technical performance, but is tuned so much better than the 5, with super duper bass elevation- done right, and a chocolately physical sound.
THese are my personal observations. Just sharing to be part of the fun...