I bought mares puck wrist computers for my husband and I before our recent (5/08) trip to the Bahamas where we logged 8 dives with them. We're new to diving, but are doing 3-4 dive trips/year and wanted something simple, yet Nitrox compatible for the future.
We are both really happy with the Puck. It has a great big, easy to read display with the depth and no deco limit prominent. I really liked the ascent rate monitor and the conservative algorithm because our vacations are all about diving so we tend to do multiple dives on multiple days. We're all about safety and diving conservatively, but it might be too conservative for some. We definitely realized that our ascents had been a little fast before getting the computers, so the computers have definitely helped to improve our diving.
The water temp is also displayed, and I like having that info available (the rental Suunto I used in Australia didn't have temp and I was always curious about the temp). Once out of the water it switches and displays no-fly time. It only has one button, but after about 20 minutes with the manual I was ready to go.
The wrist mount is great, much easier to keep an eye on than the gauge console. This was key on the wall dives we were doing where it was easy to go very deep if not paying attention. The wrist mount made this easy to track. I was a little worried at first that the unit might be a bit too bulky on my wrist (I'm a very thin woman with tiny wrists), but it was fine, especially over a 3 mil wetsuit. There are smaller wrist units (like the Suunto I'd used before), but I liked the big display and simplicity of this computer and it is much less pricey than many other computers. Overall, I think this is a great basic computer and having computers that we are familiar with has made us safer, better divers.