I'm not sure on the relative power of the DG's, but some DG's are less complicated to play than others.
There are really no gotchas with UB, it's fairly straightforward to play. Sedna, focus on not dying, don't get Yetis, and you'll be decent enough. Lord Erebus, not as simple as the other two, but can do pretty much everything, and in the hands of a good plyer it will be very hard to kill.
The rest of the DG's, with maybe the exception on Regulus (also fairly straightforward to play, as long as people remember to invest on Mines), are more tricky. Fire TB requires careful play, Ice TB is good in the hands of a good player. QoT, needs a good player to be worth it, same for Rook, a bad Rook player just dies a lot. And Oak, can also be good, but again, requires experience.