When traveling in Puerto Rico should I get a rental car or is public transportation sufficient?
Also When is the best time of year to get Puerto Rico experience?

You'll want to re-post on the Caribbean Forum (see the 'Change Forum' pulldown menu)

Since PR IS part of the US it seems appropriate enough.

From my own experience with using a rental car on that island (which I think you'll find is better than relying on public transportation) I would very STRONGLY advise you to take out INSURANCE. I have driven in a lot of different places including places in Asia where people didn't think driving at nights with their headlights on was useful...I have NEVER driven anywhere in terms of traffic violations than on Puerto Rico; right turns from the left lane, all turn signals apparently broken, and people making a life of living in the passing lanes on the autopistas. Do yourself a FAVOR...

Thank you for the advice. Any advice on the must see spots?

Yes - Dukey PR is 'part of the US'. However for Fodors purposes (which is what matters here) - threads about Puerto Rico are on the Caribbean Forum. (There are thousands over there)

Diamont32: In fact - if the editors see this thread they will move it to the other board. So instead of fighting upstream, why not post where all the other PR threads are???

How do I change the thread?

You can't move the thread - only the Fodor's editors can do that. Just start a new thread on the Caribbean forum (use the "Change Forum" link at the top of this thread.

Another option is to click the triangle. It says 'Report abuse' but it is also a direct link to the monitors. If you click it you get a text box and can ask them to move your thread.