As Soon as you create works that are published.Which one should you join?That is up to you,either way there are pro's and con's.None of them are really geared towards indies yet if you are published you ought to be registered and have your creative works registered so that in the event you have monies due you you will be paid them.Years ago it did not make a lot of sense to do it until you were onder a contract to a major label or publisher and now the game has changed to a way that your tune may be being streamed on the net and you have mechs and perf royalties due you.It may only be 28 bucks and you can invite your friends over for a nice spag dinner and say "we got this from me writing a song!"If you are NOT registered you are NOT going to get paid by the by.I can't say for you but I want to be represented as baing professional at this fun little thing I do. And again you have got to be a published artist to apply,not just a composer/author.And you must have your copyrights in order as well.