Well, I was, well, am in still the same situation as you are. Here's my take on things:
Longines Legend Diver
- By far the nicest ever diver's watch in that category, however, the strap is really bad. You will need to change the strap if you want to use this for water sports or swimming.
Oris Aquis
- Some say the Sellita movement may (big 'may' there) be sub-standard to the ETA, but if this doesn't bother you, it's a better bet than the Hydroconquest for a few reasons, firstly, the buckle on the rubber strap. Just go physically check out the buckle on that rubber strap and you will understand.
- The blue lume is to die for
- Oris service has had quite a good track record and the parts are not costly (this is subjective to what you are comparing it to, I'm comparing it to Tag/Breitling)
Longines Hydroconquest
- This watch never really did appeal to me as the Legend Diver totally overshadows it.
Now, I would recommend you broaden your search to include the below:
Sinn U1
Oris Prodiver
I won't go into the details of the above 2 watches because the fun is where you research it and physically go see it yourself. I would strongly recommend the above 2 although budget may need to stretch a bit, but if you are going to get a diver's watch, why not spend a bit more and get a really good one.
Just my 5 sen.