I find the Cobalt to be one of the best computers my family and I have used...except for Shearwater. I have had Oceanic, Hollis and Suunto...so certainly not the full range and I have yet to try the Icon HD. But the Cobalt has been a solid and stable computer since I purchased my first one in 2012. My opinion only of course.
I've never used one personally. All of the other instructors I know used to have one but they kept having issues. Our tech said they are very frustrated with the Cobalt. In fact, what prompted our conversation last night is hat one of our Course Directors was leaving for the Philippines last night and his Cobalt malfunctioned again. He's on his 8th one. I asked him why he doesn't just change and he said he loves the computer, when it works.