From my experience (mostly from fighting against bombers), you should go for Roc or Cutlass. Roc seems to turn faster but is easier to hit (especially from top/bottom, the wings are huge) where Cutlass is more compact but seems slower on the turn. The turn rate can be extremely useful when fighting snubs, as you can easier SNAC them.
Waran is pure suicide, unless you have skilled fighter or solaris gunboat support and you are very careful not to get caught alone. In group fights you'll be targeted early because everyone loves an easy kill. In a 1 v 1 you are dead meat against a fighter. That being said, you can deliver a huge amount of damage to capital ships, and you'll still be somewhat difficult for those to hit.