Seas 27TAC/GB vs Scanspeak 9700

They are both really good.

The 27TAC sounds a lot like the older RS28A. Smooth but detailed, and very articulate. Best HD as measured by Joachim Gerrard 2k+. I used notches on both Fs and ultra resonances. 1.8k+ response. Al/MG dome. Not many have used it, only about 4-5 years old.
No ferrofluid.
Thick reinforced sculpted plastic faceplate.
Titanium former.
Copper cap.
Open and clean sound.
Lower HD than 9700.

SS D2905/9700 is a textile airy and clean sounding dome with smoother and less articulate sound than the TAC. Driver is low HD, and is a veteran using the Revelator SD1 magnet. 1.8k+ response, and no blemishes to remove or treat. Deserves accolades received.
No ferrofluid.
Aluminum face and former.
Copper in motor.
Lower Fs than TAC.
Less articulate than TAC.
A little more sensitivity than TAC.

At the price, I feel the TAC is a no brainer as the 9700 costs over twice as much.