Well I like Mortons, but I can go there anytime. Maybe if they dont have one in your city, but still I could go there when I visit other cities on vacation! I would do Steakhouse 55 for those reasons, because this is the only time you can go there!! Also I HATE to leave property when there so for me going to eat at the DLH would be much easier!!
Steakhouse 55 is wonderful. We have done breakfast and dinner here. The service is the best, and the food is great. Just know before hand they are very expensive. For myself and my mom we both only had a soda and soup, my ds7 had a kids meal, my dad had a steak baked potato and water, and my DH had a steak baked potato and a beer. The bill was $138.00. Not to bad at all for us, but it was a little steep. But didn't bother us to much we have ressies there on March 8.
We thought Granville's (Steakhouse 55?) was just ok. And way too expensive for just ok. Morton's is a heavenly culinary experience worth every penny. But as Andrea said, how important is it to eat on site and do you have a Morton's where you live? My favorite DL Resort Restaurants do not include any "chains" that I can eat at close to home. So that would be the important question, I suppose.
We've eaten at Granvilles aka Steakhouse 55 plenty of times, We've never eaten at Mortons, but have heard RAVES - to us, Mortons wins, as Steakhouse 55 is just OK and VERY EXPENSIVE for portions recieved. Now, we love it for breakfast when staying on-site, otherwise, unless you have an unlimited budget, many other better options are available!