The TC's use very high quality HF drivers & wave guides.
The Hathor's use paper cone drivers - iirc, 3" to 5" together with special rear wave chambering to openings to the top & sides of the cabinet.
Duke also has switch controlled crossovers that make the most of good driver selection & cabinet design & tuning (with port plugs for even more tunable low end options).
Please correct me if I'm wrong on any points.
I love the switches on the 1203 cabs! I played an outdoor gig last night, it was with my acoustic folk/singer/songwriter type gig. I was playing a P bass through a TFB550B into one 1203 cab. I had a little too much mid grind going on so I just flipped the switches and after appropriate EQ I was set. That gave me a smooth, clean sound with plenty of lows without boom, and enough mids to project.
Those switches just add extra versatility to an already great cab!