Like Busta said it been discussed many countless times. Use the Search button, and you will find allot. I would not say that they are a waste.
However, tactics manuevers, and command structure are more lacking than the real world. I am leader of a small all Russian themed team. We act more like that of a terror group or Militia. We are able to impliment more than the average team on using different Reenactments and tactics.
This is where I agree with Busta. You get these groups of teams all that use the same Amercan based tactics and gear and act the same way it becomes a waste. Having a team that has a theme or unique purpose adds a different perspective, and Purpose.
