I apologize in advance for many of you who have heard this before . . . I am a big fan of the sealed bass in the CS3 and 5 series. In fact, Thiel was philosophically committed to sealed bass in its upper models, while allowing reflex bass in its lesser models with the cost savings reflected in the lower sell prices. The main advantage I see in sealed bass (whether equalized or not) is the phase / time coherence all the way down to the low limit, and then 12dB/octave to subsonics. That is radically different from reflex bass which attenuates the woofer at 24dB at its bottom and the port at 24dB at its bottom and top rolloffs. That puts the foundational deep bass a full wavelength behind the upper frequencies. That's 20+ feet, depending on actual tuned frequency. Philosophically that runs contrary to Thiel's committment to wavefront integrity.
When that direction was coming to be in the 3.6, the mood was more relating to what others' products (even with 6-figure prices) were getting away with. Some of us are more sensitive to the philosophical integrity, and others notice the sonic discontinuity of reflex bass. Note that Thiel reflex bass is executed as well as I've heard it. Look at the clean graphs and the tight tuning. But . . . it's still not the real thing.
