I hope I did this reply correctly
I LOVE MY SUUNTO. I took my OW classes using the D-9 wrist computer. Very cool piece of technology, loved the bells and whistles, but the face of the computer was very small and very hard to read. I gave that back to its rightful owner and bought the Cobra.
Here is my research: The Gekko is very similar to the Cobra. The biggest difference (other than a few $$$), was the PC-download. The Gekko does not seemlessly connect to the Suunto Dive Manager software. Being a computer geek, it was important to me to download my dives to a laptop.
I love the ease to use, the clarity of the display module, and the preference settings. Same with the compass. It is very easy to read and is as stable as possible under the conditions.
The Cobra II has a few more bells and whistles, but it is even more $$$ than the Cobra and has the electronic compass. The D-9 had the same compass, and it was incredibly hard to read and use. My advice would be to save the money on the Cobra II and opt for the Cobra with analog compass.
I didn't start to "get" the Cobra until after the first dive. Of course, mine was new so I didn't have any dives in the history. But, I had to first play, then read the manual, then compare the computer against the manual and then dive again.
The manual was written pretty technical, and you have to hunt and peck for the right graphics, but once it starts to click a bit, it all falls into place.
If you like the Gekko, but want the PC download ability, you will really like the Cobra. If you don't need the PC download, then the Gekko is a great computer. About $200-$300 dollars less than the Cobra.
I hope this helps. Happy diving and good luck as lead diver.