Welcome to cruise-chat. I was on an Alaska cruise on the Star in August and without question for the best steak dinner on the ship make reservations at Cagney's. Here is an excerpt from my mega-review of this ship regarding Cagney's:
"Cagney’s Steakhouse was a classic on par with Ruth Chris’s. The room is attractive and comfortable. It reminded me of a traditional “Chicago Style” steakhouse. Although Cagney’s is the most expensive of the alternative dining choices ($20 cover), it is definitely warranted. I could have dined here nightly and gladly paid the additional cover. My filet mignon was perfection! It was perhaps the most tender filet I have ever had and veritably melted in my mouth. The waiter was attentive and personable making the dining experience that much more enjoyable. Dining here was a real treat and I delighted in every moment."
You will find a very good steak at Le Bistro also, but if everyone is planning to order steak - Cagney's wins.