I have the Cobra with a quick disconnect that was added by my LDS. I have a suspicion, it isn't a Suunto quick disconnect, but rather a disconnect rated for the high pressure side. But it does work well.
I find I use the quick disconnect for all the reasons everyone else mentioned, but also for one other thing. Since the Cobra with a compass is fairly long, I find it easier to store my ADS with the Cobra disconnected and a couple of end plugs inserted.
I also have a SPG that I can plug in just in case the Cobra should have a problem, also on the same quick disconnect. And before anyone says anything, I don't plan on doing the swap out under water. But I do use it for pool training sessions, so I don't have to mess with the computer logging the pool dives. I have a spare Mosquito computer, that I use on vacation, so at worst, I will have to loose one dive if the Cobra failed.
My LDS swears by the Cobra for reliability, almost everyone in the shop has one, and I don't think I have heard of any problems with them.
Now, as to the computer interface, the program on a scale of 0 to 10, ranks about a 5 at most. They charge for the cable, not the program, and the quality of the program shows. I can't compare to anything else out there, so I can't give you a relative answer. The rating is in comparison to commercial software in general. In general its a clumsy program, with some useability problems, and it has been known to corrupt the data file, so keep backups.
Personally, this winter, I will probably go to a simpler log that keeps the data I want, and drop the Suunto program. It was fun at first, but now its more hassile than its worth.
Oh, and as to eyes, I can read it with 44 year old eyes, but I'm not sure I will be with 45 year old eyes. I use bifocals in my mask that helps with that and other tasks.