I really liked the AW100. I did have a few flooding issues with it, and I was carful, but still may have been my fault. Letting it dry out for a day or two fixed it every time, which I was impressed with. I ended up trading mine in and upgrading to an Olympus e-PL5 (not really a comparison, but I wanted it). I was able to do that because I purchased the 3 year any reason AD guarantee from Best Buy. The lens does have a tendency to fog up between dives if you do not keep it in cool fresh water, and if that happens good luck shooting anything the rest of the day. I'd figure out that if I traveled with mine in a thin Rubbermaid bucket with a lid, I could use that to keep it in fresh water between dives.
I too am considering the AW120 as a backup point and shoot, since it has WIFI. Also, They do take decent pictures and have some pretty fun software for effects and 180-360 panorama shots. If you pick one up, I'd highly recommend getting some underwater colored filters for it. They help get rid of the green and blues that take over at around 10 ft+ deep.
Note: The two times it flooded was in salt water. Yet, it still worked after drying out. Had it and used it regularly for at least a year after the first flood, and then maybe a month or so after the second.
The unit is very solid and can handle a lot of shock. It really does withstand the shocks and the depths it is rated for. I bet if you put it in a clear ziplock or vacuum sealed bag, you could take it much deeper than it is rated.
I am not sure about the AW120, but I did wish the battery would last a little longer. If you are just taking pictures and very short videos, you will be fine, but it seems like it was only good for about 30 minutes of video. Turning GPS off may extend that, but it was not by much.
The AW120 has some cool compass, orientation, and gauge features too. It, might be fun to use those on a <18 meter deep dive.
---------- Post added May 29th, 2014 at 01:16 PM ----------
As a quick follow-up: This had me thinking about my old AW100 camera again. So, I just picked this AW120 up today as a pocket point and shoot to take with me where ever I go. Mabey that is an indication of how much I liked owning the AW100.
I have my phone to take pictures, which works ok, but is limited. With this, I can take pictures and connect to it wirelessly with my android or my wife's iPhone and use it to quickly update our social networking sites. And the pictures and video are many times better quality than a phone will get. I feel it is the perfect companion for my Wife or Daughter to use when they Snorkel. Also, I won't let my son dive deeper than 18 m until he is older, so he can use this as his camera too.