I got the Suunto Cobra after hearing raves from my OW instructors. Haven't used anything else, so can't compare. Though there are some aspects of the Cobra that I find lacking (though I'm a new diver, so this could all be bogus):
First, the software which allows you to download the dives to your main PC is kinda limited. For example, it doesn't allow you to plot air consumption vs. time, which is kinda surprising to me. Would be nice, especially for us new guys. Also, there's limited indication of whether you exceed the maximum ascent rate. I guess that's tied into the fact that the minimum sample interval is 10 seconds. I think you could exceed the 30ft./min. ascent rate by bouncing up and down within the 10 second interval, but not have any indication when you graph it. A good example would be this: you are ascending, the computer samples your depth at 10ft, then at the next sample time 10 seconds later you are on the surface. All the computer can assume is that you ascended at 60 ft./min. (10ft/10 sec.). But it could have been much faster. I guess I'd like to have the option of a shorter sample interval and less stored dives. And it would be great to have an indicator of the highest ascent rates experienced during the dive. It would also be nice to be able to load an actual dive into the simulator so you can tweak it and see what happens, instead of having to enter point by point yourself. Maybe you can do that, but I haven't found how.
Second, as best as I can determine, tech support means either a call to Finland, or sending an email and waiting for a response. Not bad, but not the greatest.
Third, there are some things about the computer itself which bug me. For example, there seems to be a discrepancy with the STOP indicator when entering the 3 minute recommended safety stop. Sometimes the STOP indicator doesn't appear. Bugs me. I've got an email into Suunto on that one. Also, during surface intervals it doesn't really give you much information, other than to give an "attention" symbol if it thinks you need to extend your SI. Not sure exactly what I'm looking for, but maybe something like an indicator of how your pressure group is dropping while you're waiting.