Two questions that need to be asked.

1) Are you planning to attend any club's activities/events? If yes, you must have an AMA to participate/join most clubs. Even if you're not a club member and you decide to participate only in a clubs's event, you must have an AMA card.
If you don't plan on doing anything like this, no, don't join. It would be senseless.

2) Are you a homeowner? If not, then joining wouldn't be such a bad idea. If you are a homeowner, don't join. If you are a homeowner, you must have homeowner's insurance. If you are ever involved in an accident, your homewoners is going to have to be the first to pay on a claim, not the AMA. So therefore, if you are a homeowner and still decided to pay to join the AMA, if you ever have an accident and expect the AMA to jump all over the claim, you're very, very wrong. It's your homeowners that must pay first. Pretty crappy huh!

So, should you join? Ask yourself these questions and get back with me.