Going to a digi SLR was the best investment I have ever made for my habit. You will completely enjoy it. Regarding what housing to purchase, you will need to consider a few things.
How much doe you willing to spend?
Most housings are similarily priced, but some are more than others.
Personally, although I think an improved design is in order, I went with the Light & Motion Titan D100. I use my Subal ports with it. They have an adapter ring that allows you to use any of your Subal ports.
The thing that sold me was the ROC feature. I can shoot a pic and adjust my lighting, F-stop and shutter speed without moving a muscle, well my thumbs. There is no cumbersom movement to adjust strobe or move dials. You will get more good pictures with this digi housing than any other digi housing (in my humble opinion) solely because of that feature. I had a barracuda encounter a few weeks ago and came away with so many good pictures that I don't know what to do with them. It was because I didn't have to move any limbs to make lighting adjustments.....I remained still and didn't scare him away. Here is one of those pictures.
Now I will probably get flamed for this statement, but my portfolio has improved drastically because I don't scare away too many skittish animals, and ultimately get the shot.
To be fair, here's what I don't like about the housing.
1. The sync cord bulkheads and aiming light mount are bundled, way too close together, so it requires me to have a long aiming light arm.
2. It is top heavy. Try to gently rest the handles in your palms and the housing topples forward.
3. It's heavy.
4. Has a lot of o-rings to service, and you dare not mix them up, or you WILL flood the system. However, I do like the comfort of a dual o-ring seal.
5. The viewer is small. You really need to rely on the cross hairs to compose your shots, because unless you look sideways, up, down, etc. in the viewer, you don't see the whole frame. So, you'll take a shot and see that "crap", "half of the tail is out of the frame:)"
6. It's all electronic. Really no manual controls to speak of. If it fails, you better have back up electronics with you. AND THAT's WHY I ASKED YOU HOW MUCH MONEY ARE YOU WILLING TO SPEND. I have an extra $1,000 tied up in electronic redundancy, because I am anal and don't want to miss a trick while diviing. I can rebuild the entire housing in the field if I had to. But at a hefty price. Plus, my wife has no clue I blew our bonus money on the "spare parts" I have. Shhhhh, please!
BUT, the ROC is worth the extra costs for me. It's all about getting the shot, right?
Hope this helps you.
Joe