Is there a reason you are splitting amongst 3 MDRs? I think the advantage of sticking to a single MDR is the likelihood you will be recognized by the staff and treated with just a little more personal service. There are those among us here who long for the days of traditional dining. If you are one of those, you may find the experience more to your liking if you return to the same dining room night after night.
We had the same headwaiter each night and got to know him pretty well, and vice versa, We did not see the same server every night but when we did get a repeat, he remembered us from a couple nights earlier. Being served by the same staff just makes for a smoother experience, like knowing not to put butter on my bread plate or remembering that my wife drinks cabernet so that a drink reorder took a few seconds less.
And as several others have pointed out, you may be able to secure the same table and server for the entire cruise which elevates the experience just that much more. Part of the pleasure of cruising is being treated as if you are much more important than you might be in real life. This helps with that.
Of course, none of this might matter to you. But if it does, something to consider.