We took MOS 5/6 and it was our first cruise ever and I hate to tell you but you will be HOOKED! The down side is once you cruise this ship, you'll never want to cruise anything smaller. Our first night out we had a bad storm (70 mph winds). Yes, there was rocking, but even still, not nearly as bad as i would have thought.
My best suggestion (and it worked for us) was get a cabin mid ship, both in deck height and front to back. Sure helps with a smooth ride. And we splurged for the balcony and LOVED it.
Also, you will want to over pack. Don't. Go ahead and remove some of your packing. Use their laundry services. Hubby over packed and still used their services. 2 shirts, 1 pair of shorts and tip was $10. And that was 24 hour turn around. Not bad!
Pace yourself, enjoy and you'll have a great time.
Past Cruises -
Rhapsody - Alaska - May 2010
Monarch - Bahamas - May 2009
Mariner - Western - May 2007
Mariner - Eastern - March 2008