The answer to this question is entirely dependent on the people involved. What makes it worthwhile for one person may not be what another finds advantageous.

To gve an idea of the basis of my opinion: We are a couple, married for nearly 16 years, poly from the start, actively playing with others for 11 years, have met literaly hundreds of people in the lifestyle through various events and clubs (we have played with VERY few though, we're easy, not slutty!), we host a monthly dinner gathering for the single purpose of socialization, and have been in an exclusive triad relationship, or poly fidelity, with our girlfriend for nearly 4 years now.

So!, all that said here are some basic things I have found through dirct expereince and observation:

• Most people that are successful in the lifestyle are excellent communicators, you have to be if you want your relationship to last more than 30 seconds.
• Many in the lifestyle are very honest, open, and freindly people, the kind of people that make good freinds. You're very likely to meet lifelong freinds in the lifestyle, even if you never play with those people.
• In our case, we have found that we're more like best freinds than the typical married couple, we hang out and look at girls without having to worry about anyone getting jealous (no purse whacking!).
• The reality is no matter how good your sex life is now, it WILL fade. Being able to bring others into your bed from time to time helps keep things fresh and interesting between you and your primary partner without anyone having to cheat to get something new.
• In the case of having a regular playmate, or better yet, have a live in like us, your personal support at home is that much more solid. One person or another can go off on a trip and the ones left behind have each other to depend on should something happen while the other person is away.

Now these are just a few things really, but they are the ones that stand out for me. There are just as many, if not more disadvanages too. Again, all depends on the people involved, everyone will bring their individual set of issues, good and bad, to the relationship.