It's down to taste more than anything. Personally, I find I do better with Iron Hammers than any other 600ms codenames, due to the way the projectile looks. I just find it easier to aim. Some people swear by Blue Blazes, altough personally I hate them. Plenty more will point you to Excaliburs or Heimdalls.
2.00s are all about alpha damage... Hit once, and inflict a lot of pain. So anything with more than 1300 hull damage is fine. The only possible exception is archangels, which use a tad too much energy for their 1400 damage. Although even they're pretty damned good.