Scotty, Ah - your first competition as a spectator. I remember being dazzled, humbled and inspired at the first big competition I attended.
Personally, when I attend competitions, whether as a competitor or spectator, I watch EVERYTHING: pro/pro, am/am and pro/am. Personally, I find that there are strong and weak couples in all of those categories. There are some pro/am couples that I would prefer to watch over some pro/pro couples. However, in answer to your question, I find on this board that many posters are very dismissive of the amateur half of a pro/am couple, and would lead you to believe a female student is just being lugged around by her pro, and those posters, no doubt would advise you not to waste your money on a session to watch them.
Certainly, if you can afford to pay the entry fees to watch multiple sesssions, that is exactly what you should do. See the whole variety of dancing - from the newcomer pro/am students all the way to the pro/pro finals, and make your own decicions about the strengths and weaknesses of the different levels of dancing that you see.
Also, be sure to leave enough time to browse the vendors - make-up, jewelry, shoes, dresses. Set a budget! I hope you have a great time at the event you choose to attend.