I ran 3 drakes in level 4s for a while before I jumped ship (lol) to Rift. They're cheap, relatively fast, shoot inexpensive ammo and don't hurt all that much if you lose one by accident. If you have the money to fit the more advanced T2 BS builds, that would work as well (and can kill L4's faster than BCs) but it is a LOT more expensive. Whichever you have the skills and investment for. If I had the skills for Paladins or something really good at long-range beam weapons, I'd do that judging by the videos I've watched. (Golems just seem like they're too....close to the edge of micromanagement, and shoot expensive missiles.)