I had a Droid X, preordered the Galaxy S3 and had it for 3 days and returned it for a Maxx. The S3 is a beautiful phone, the rave reviews are mostly right. I couldn't get used to the feel of the phone, even though it's virtually the same size as the Maxx, the rounded corners made it feel bigger to hold. I found that all the touted features were pretty much useless to me, the goofy nature theme, swishy opening screen, etc got old immediately. The one feature that was great was the Smart Stay, where the camera watches to see if you're looking at the phone and keeps the screen on.
I ended up customizing it and it ended up looking just like my old X so what's the point. I'm loving the Maxx, just feels right.
Your mileage may very.