For the dive computer, the problem usually isn't the hardware, it's the software. I can't name a dive-log program that runs on the mac AND interfaces with mainstream dive computers.
That being said, connecting my Vyper to a Mac is a no-brainer, and pulling raw dive log data isn't a big challenge - but I wouldn't want to operate that way.
If you want a dive computer for the benefits that a dive computer offers during the dive, then go for it. If you want to see your dive data on a Mac, then perhaps it's time to find someone to write some code. Sounds like there's a market for it.
Dave