THeres a few considerations when it comes to brake levers:
1. Return Spring - makes the return and feel much better, also good for the somewhat more sluggish routing on TT bikes. Also all brakes have one now
2. Size - the smaller and skinnier the brake lever, the more aerodynamic it most likely is. The 3T is really good in this respect
3. Cable routing - some attach to the internal cable, some have attachment outside the bar that you must then run inside the bar.
4. Attachment mechanism - the DA ones are like many in that they attach with an expanding plug. The 3T is more unique in it's attachment method, its a pinch system.

The DA79 seem outrageously priced to me. The DA78 got good reviews for being a compromise of aerodynamics, weight and good lever feel. The 3T to me are one of the best out there from an aerodynamic and weight perspective.

If I ever replace the Bontrager levers on my bike, I'd probably go with the 3T myself.

A good option that may be easy to overlook is the Tektro Rx5.0.