The difference between Union and non-Union are that an actor who is non-union may NOT work on a Union job. Conversely, a Union member MAY work on a non-union job, ONLY if they are FI-CORE (see 'What's FI-CORE?').
The main Union for actors is SAG-AFTRA (see 'What's SAG-AFTRA?').
Fi-Core or "financial core" status is an option within the Screen Actors Guild allowing actors to work both union and non-union jobs.
Some in the industry say that it is becoming more common lately for actors to join Fi-Core than SAG-AFTRA. The reason being that in hard economic times, rates for jobs have to be reduced meaning that production companies can't afford the SAG-AFTRA Scale Rate for talent. With more and more very good voice over talent on the scene, it becomes easier for producers to choose from a great pool of non-Union talent for a lot less money.
As an actor being Fi-Core means you get the best of both worlds to some extent. However, SAG-AFTRA does not particularly like Fi-Core members. They only see them as 'Fee Paying Non-Members' of SAG and state that as a Fi-Core member you shouldn't market yourself as a SAG-AFTRA member. This means there can be a lack of support from them as well as certain jobs potentially not employing Fi-Core members.
The following excerpt is taken from Actor's Who Make Money:
"Some of the rights you lose when you declare financial core are:
• The right to vote in SAG elections
• The right to hold SAG office
• The right to use iActor, a web service run by SAG
• The right to represent yourself as SAG on your resume or on the Internet
• The right to call yourself a member of SAG or have a SAG card
• The right to re-join SAG without a formal hearing and without repaying the initiation fee
Some of the rights you gain:
• The right to work on non-union projects
• The continued right to work on SAG projects
• The right to pension and health if you qualify under SAG rules
In order to become Fi-Core with SAG, you must first join SAG. You pay your initiation fee, and start paying your dues. (Even after you turn in your card, you still have to pay your dues and fees. Your dues will be 5-10 percent less, however.) Pension and health is completely separate from the SAG office. Don’t worry about losing those benefits."
The 'To Fi-Core, or not Fi-Core' topic has been heavily discussed and debated for years so at IVG, we think it's up to you to research and decide what is best for you as an actor.
SAG-AFTRA Is the Union representing all actors employed on UNION recognized work in the US. You must be a fully paid member of SAG-AFTRA to work on these jobs. The acronym stands for Screen Actors Guild and the American Federation of Television and Radio Artists.
Essentially to join you must first work a SAG-AFTRA job, when you are offered your first union job, you are urged to consider joining SAG-AFTRA. This is a commitment though, once you are a member, "you must abide by the rules of membership, starting with Global Rule One. And, whether you are a SAG-AFTRA member or not--never accept work during a union strike!"
After this first job there will be initiation fees and they will check the legitimacy of the Union job you did. There are huge benefits to being in the Union such as Scale Rates (set rates per job), health insurance (if you earn enough for the Union), monitored residuals (e.g. you get paid every time the spot airs) and general protection from low rates and delayed payments etc. The downsides are that if you are solely SAG-AFTRA, you can ONLY work on SAG-AFTRA jobs, and that the fees you pay can be quite hefty.
The main Union/non-Union differences are that an actor who is non-union may NOT work on a Union job. Conversely, a Union member MAY work on a non-union job if they are FI-CORE (See 'What's FI-CORE?').