If he's serious about tech, or if you want absolute top of the line, the Petrel might be the only way to go.
HOWEVER, it's drastically overkill for the VAST majority of divers.
Well, I guess I was responding to the OP's question about getting her husband a "fabulous" present for their anniversary and his birthday. It seems that the Petrel would be a good candidate based on that, but of course I don't know anything about their relationship or their finances!
I think that if you dive the Petrel in rec mode, you have one of the best computers available for even a new diver (based on the points I mentioned, not based on it's tech capabilities). Of course her husband could get plenty of use out of an entry level computer, wasn't implying that. But for a big gift, it's something to consider...