I purchased an Atom last Friday night before a dive on Saturday. I used in on 2 dives and was very impressed with it, although I had a concern with the screen. I didn't really notice while diving, but while on land if viewed straight on, it basically dissapeared. I had to tilt it to see the LCD. I don't know if this is an a feature for diving so you don't have to turn your arm to see it and can just view at an angle.
Anyway, I pulled it out Sunday night to review the logs. I put in on my wrist and before I had a chance to press any buttons I heard a beep. Once I realized what was beeping I looked down to see it had reset itself with time and date back to start.
I checked battery status and it said okay. Battery was packed new and put in on Friday night. I packed it all up in the box to return it. A few hours later I checked on it again. I took it out of the box, again pressing no buttons, and heard it beep and reset. This time the battery said low. I opened the case to check for any signs of water intrusion, and it was dry. Reinstalled battery and the unit went dead.
May have just been a defective unit or even a defective battery, but I just lost confidence in the computer. I ended up returning it and getting my wife and I Pro Plus 2 computers.
I like the large screen and additional information you get on these. Very simple interface with lots of info.
In the end I thought the Atom was "cool" but wasn't totally confident in it's build quality. I feel much better with the Pro Plus 2s. If I ever go with a "watch" style computer I will probably choose a Suunto. I own a few of their products and feel their build quality is much better. I like they fast they use a real crystal on their face and not just plastic that will easily scratch.
I will say that the Atom software, while not very good, is much better than the Oceanlog software for the Pro Plus 2. I hope they move these and other computers over to the newer software soon, but who knows if this will ever happen. In the mean time I purchased Scubase.