I had the GS3 for 2 days and the MAXX HD for a week, trying to find a suitable replacement for my Thunderbolt (Both phones I returned).
The GS3 was a great phone for the time, fast, great display, great camera, etc. However I hated the slick back plastic, I came really close to dropping the phone several times. The signal is slightly worse than other phones, last night me and a friend were at the movies, she has a GS3 on Verizon and I have a Thunderbolt. My Thunderbolt was getting 1-2 bars fluctuating between no data, to 1x, to 3G, where she was not getting any service at all (she even put the phone next to mine and no luck). Battery life was fair, it could last a day but I hate going into the night with only 20% battery left, as you never know if something will happen where you won't be able to charge your phone for several hours.
The MAXX HD improved on a lot of these, but I use the camera quite a bit, so that was a major deal breaker for me. Even in bright light the photos were awful. The ergonomics IMO were horrible as well, when I held the phone the sharp edges (relatively speaking compared to the GS3) made it uncomfortable to hold for an extended period of time. The edges as well as the squarish design made it look like I had a deck of cards in my pocket, whereas the GS3 with its tapered edges made it more comfortable and more discrete.
All in all neither phone was worth the $600-$650 I paid, and ended up returning them. I tested out the Note 2 and while it's a HUGE step up from the GS3, it's slightly too large and doesn't fit in places like my cars cup holder that I usually use to store phones in. I'm hoping the DNA is that perfect device.