I can’t speak to DA 7900, but I do own SRAM Red, Zero G, Ultegra and Campy Record Brakes(the newest ones).
When evaluating braking performance, they are all good but I think the SRAM are the best and I’d rate Zero G as the worst.
Zero G’s look cool are light and they honestly do work well. I’ve ridden them a lot and believe that with good brake pads and attention to set-up they do the job just fine. However, I do think you give up a little in terms of pure stopping power. I know that if I were to come up on an unexpected hairpin curve down a 10% grade at 40mph, I would simply be more comfortable and confident with SRAM, Shimano or Campy Brakes.
Zero G are more finiky to set-up. If you have them set-up to actually stop you, I don’t think the calipers open wide enough. With 23mm tires like Michellin that tend to be on the wide side, you sometimes have to dump a little air pressure to get them in and out.
All in all, Zero G’s are perfectly good brakes. I wouldn’t hesitate to use them and may end up putting mine back on my TT/Tri bike. I just decided that for my road bike I was more comfortable with other options.