Have been to kitkat plenty of times. It cool especially if you are bisexual. But if you are straight or gay you will spend a lot of time saying "no thanks".
Be aware that the two doormen lack even the basic skills of a service minded host. They are extremely rude and will reject anyone at the door without reason. They are not even capable of maintaining a line, resulting in people jumping in front all the time. If you bother to cope with this, then a lot of fun await you inside (unless of course it's a quiet night, which is about fifty fifty).
Berlin is one of the most popular gay destinations in Europe. Many bars, clubs and parties seem to have a darkroom. Opening times are unrestricted and you can party round the clock. The beers are cheap, and the guys hot!berlin gay nightlife guide