Well, they are quite different. Depends on what kind of meal you want and if you have little ones etc...
H&V is a buffet. It is good if you want a cheaper meal and if you have picky eaters or little ones that you don't want to worry about the noise factor.
As buffets go, I think its fine. We ate there several times with the package when our girls were little.
MM is a sit down menu meal. A little bit quieter, more relaxed atmosphere and you'll be waited on. More expensive than H&V. They have a yummy menu and good desserts too.
If you don't have little ones (and even if you do really) and don't care about money, I'd go with MM but they're both fine...just different types of meals.