On our recent passage to Hawaii (Jan/Feb 2014) from Long Beach, Ca to Hawaii we spent 5 days heading West and 6 days heading East. We were plagued by rough seas and high winds (up to 70 knot gusts). The Carnival Miracle, which is a fine Ocean Cruiser, was seriously pitching (front and rear) and rolling for a bit more than 5 of the total sea days. We were unable to make port in Kona, Hawaii due to the wave action. Many of the veteran cruisers suffered sizeable bouts of Mal De Mer (Seasickness) and many passengers were spotted wearing patches behind their ears!!!
Fortunately, Our experience in choosing a lower deck balcony located midships proved its weight in gold as we were quite comfy and had no issues. Karen, my SO, wore a Seaband for about 3 hours. Dinner at Nick and Nora's Steakhouse up on Deck 10 Aft was a trip...We kept watching the Hostess carefully stagger around on high heels as the ship pitched and rolled. She handled it well....Dining venues were never too crowded (understandably)!!
Given Our recent Pacific Crossing experience We would, without hesitation recommend Lower deck, midships for inexperienced cruisers. Don't You ever wonder why future Naval Officers in Training are called "Midshipmen"?