i have been diving a Galileo Luna for over 4 years, 365 every weekend minimum. I just got around to changing the original battery on the wrist unit last week. real easy to change, grab a quarter, turn the slot and swap the battery. Keep this in mind, as some vendors make you send the unit in to change the battery.
air integrated x-mitter, compass, trimix capable and rock solid reliable with a very low failure rate.
downloads are a cinch too, no more log books.
its much bigger than some of the wristwatch styles you see which makes the display easy on the eyes...especially when you're narced out @ 130'
I noticed a bunch of problems with the Suunto D4's with premature battery failure and some of them going on the fritz early on.
There was a "glut" of units here when they ran a special on them a couple of years ago, so a lot of people had them. Might be hit and miss if you get a good one. I had some buddies on their 3rd one in under a year. i think they fixed a lot of issues with the d4i.
you wanna break the bank, the shearwater petrel is what all the cool kids are diving....its more of a tech dive computer, but has a bit of cross over to rec diving.
good luck and good diving!!
c