Dunovs become gold when they turn level 6 and can use flux field on your other capital ships. All your other capital ship's abilities are suddenly only limited by their cool down time. The problem is before then the only ability it has worth it's anti-matter is magnetize, and that is situational. Restore shields is far less effective at keeping ships alive then Hoshikos/Repair bays. It also has ridiculously damage output.
So, for a Dunov to contribute...
1. It has to reach level 6 (not an early game cap).
2. It has to be supporting other cap ships (not a good first cap).
3. It need supporting frigates to deal damage (not a good first cap)
I play multiplayer about 99% of the time these days and for TEC I recommend the Sova, Akkan or Marza as a first cap. If you play single player you can basically build whatever makes you feel warm inside because it isn't that important to the outcome of the game.