I have taken my SR1 down to 185 feet and, even allowing for narcosis, the ease of breathing is astonishing at that depth. Any deeper and you should have helium in your mix anyhow. The SR1 got a bad rap from an early design defect (which caused the environmental seal to pop), but they seem to have worked out the kinks now.
I also use a D9 - when I did purely recreational diving, I wasn't too keen on it (too conservative), but I got to like it a lot more when I started tec diving - partly because you don't mind conservatism when you are decompressing anyhow, but also, I honestly think it is less conservative (in relative terms) when conducting decompression dives on nitrox mixes. Not sure I wouldn't go so far as recommend it (it is a pretty titchy screen - if I was starting from scratch I would probably look at a Galileo), but it is certainly not a bad option.
I'd pass on the Cobra. No gas switching capability.
Just my 2 psi.