Depends onwhat you call a zerg.

I'm a co-leader of a group of 10, comms can get messy, people can not like eachother, but with some discipline and decent leadership it can be a real good experience. We never do anything as 10 players, at max we go out as 4-5 because if there is any more, comms get too messy to communicate. It gives every player a chance to perform their niche. A guy who can't do any PvP but is an amazing builder/electrician gets served all the resources he needs. Some dude who can farm like fuck but can never use that farm to get in top can get some help from the 3 PvP chads in our group. The PvP chads who get loot by killing rather than farming can get bps for guns and armour much quickly when in a big team.

If a clan/zerg is managed effectively, it's amazing to be apart of.