The best squad in this game is the squad that accept you despite your flaws, respect you despite your differences. A squad is like a marriage or family in many ways.
The best squad for me personally has always been The Unforgiven. I believe I am the only Englishman to have ever flown for them (we have a couple of Scots) and once or twice there has been confusion and upset due to our cultural differences, aye, and language differences, but like any family we have grown together and learned not only to respect our differences but also become a stronger family despite them.
So the best squad? The one that contains your brothers. Be it WoT, be it Muppets, be it CJ's be it DM's. If you can show them the worst of yourself and they still accept you, you're in it.
