I’d say it prioritizes different things, you can definitely own both and not have any conflict.
The crassi has that more relaxed w signature that has a bump in both bass and midrange so much more meaty and prominent in those areas, and a smoother more relaxed top end but still with a bit of extra upper treble sparkle. Compare that to the more clean and lean forward v approach of the sarda which is more linear in the bass, more recessed in the midrange, and more overall prominent in the treble.
Stage wise, the crassi is more large, wide, and a few steps back, where the sarda is more close, in front of you and forward in it’s stage. Sarda does have sharper imaging and more depth, but the crassi just has more space and width to play around with.
When it comes do dynamics, I do think the sarda is more lively in macro, and about similar to the crassi in micro.
For impact, it’s no doubt the sarda just hits harder in the low end and treble, but the crassi does have harder hitting mids
For resolution, I think the sarda has a slight edge but admittedly close enough.
For timbre, I do think the crassi has the edge here, and also has the edge in general organicness
For speed and separation I do think both are good here, but sarda has the edg
For tonal density the sarda is definitely more on the lean side of things, and the crassi has more meat on the bone
And in overall smoothness I find the crassi to just have that better liquidity to things without messing anything else up because of it
Also, when it comes to texture, I would say the sarda has a bit better overall texture (mainly in the bass), but the crassi does have better texture in mids than the sarda
Overall they are definitely aimed at different audiences/goals for sure, I could definitely see someone owning both