It depends on what you like.
The three best steaks I've had on property were on at the Cali Grill, Narcoossee's, and The Yachtsman's, where I also had my wedding reception. I've never been to Shula's because I don't Don Shula, the Miami Dolphins, or the Dolphin resort.
If you like a great wood fired steak, then The Yachtsman is for you. The California Grill has an amazing filet with a nice Teriyaki Barbecue glaze. It's light and more of an accent than a normal BBQ sauce. Narcoossee's has an awesome fillet in a sublime red wine reduction. Based solely on the steak it is hard to pick. I have literally had the best steak of my trip at each of these venues. I've never had a bad cut of meat at any of these places.
The Yachtsman is the most steak oriented. You will have your choice of cuts. While all three are "nice" restaurants I think The Yachtsman's would be the best for the kids. It is a little more open and relaxed.
Narcoossee's should be you're choice if you are travelling with seafood lovers. Their menu is more of an upscale twist on hearty American fare. It is the tightest and quietest of the three venues. If you have a cranky kid after a long day this would be the worst place for a melt down.
The Cali Grill menu is the most challenging menu. It combines flatbreads, sushi, and an international flare. This is the loudest, brightest, and most modern of the venues.
I hope this helps.