I know there was a lot of discussion about this a year ago, but today, knowing what we know now that Maxx has been available awhile, with Lenovo purchasing Motorola, etc.
Although, I have the GS4. I like it, but I have a few problems with it. For battery life I get 6-7 hours on a good day. The camera is really just hit or miss. I personally hate TouchWiz, but I know some people really like the features.
Now that Google owns Motorola, I'm sure they will push Android Updates faster, so that's a plus!
It's really just personal preference. Here are two sites to compare the specs: