Anyone is/been in a Quad (polyamorous)?

[reflexk]

I had been following this thread and made me fantasize about a dream/fetish/whatever-you-call-it which I had been having from as long as I knew what sex was all about.
Basically, it is about being a part of a quad - two couples coming together as a couple-of-couples; with each person having 2 partners (or 3 in case of bisexuals, which I am not btw).
Isn't it just awesome fun to be hanging around with and being in bed with more than one partner without any sort of guilt, never being have to hold back your horniness when your partner is not in a mood, having that time of the month, busy with work etc.
Being in a quad is different from swinging - the latter is more of a casual thingy, the former is more of a mature relationship.
Lots of advantages, but I am sure there are disadvantages too -imbalances in affinities caused by politics, ownership of children etc etc.

Any bro is/has been in such an arrangement?