First, let me warn you, there are few issues in diving that have more opinions backed by less data that dry suit selection. I doubt if there are more than a few divers on the board here who have, long term, dove more than one or at most two different designs of suit. Dry suits are very expensive items and folks get real ego involved when they make multi thousand dollar decisions, if you know what I mean. Most folks dive what their instructor or LDS tells them to, and unfortunately most Instructors have limited dry suit experience and most LDS only have one or two brands of suit to sell you and dont really understand the advantages and drawbacks of even those suits. Let me give you an example, drawn from the question of wetsuit selection, but it addresses this problem and should help you to understand what youre up against:
I issue a very detailed equipment list before each class that students who are accepted into the class need to purchase and show up with at the first meeting.
The suits we were using at the time were, as Ive mentioned elsewhere, 5mm, skin two side, Rubatex GN-231N, attached hood, farmer johns, no zippers. I send my list to all the LDSs in the area and freely distribute whatever they send back to the students (this is a big deal to the shops, in the dead of winter, twenty full sets of gear with no selling or inventory required: take the order, take the money, and deliver in two weeks).
One student did not go to an LDS, but rather to a shop near her home, about a hundred miles away. I got a call from the Instructor in the shop informing me, in a fairly emphatic tone, that, No diver could possibly wear this suit. They could not put it on without a zipper. Now, please understand that Ive been diving this suit design since the mid sixties, and the only people who need an inverted half zipper in the jacket are incredibly curvaceous women of petite statue. This woman was just shy of six foot, very athletic and quite thin.
Having nothing better to do (and considering that the woman in question was one of the brighter marine geologist grad students), I drove up to the shop later in the day. I brought my suit with me. I showed the Instructor how easy it was to put on and take off, etc. We solved the problem, but the bottom line was that this Instructor, well meaning as she was, had not yet worn out her first suit and was repeating what her Instructors had told her. It wasnt a marketing issue, the LDS could and did supply the gear (and nicely matched the prices of the LDSs that had sent fliers).
The bottom line is that for dive gear, real information is hard to come by. Most of the opinions that you see on the net are biased either by being the only piece of that class of gear that a new diver has ever used or being a loaner that the expert tried out on one or two dives.
The thing that you need to do is find an expert who is doing the kind of diving that you plan on doing and ask him or her about the gear. That may well not be an Instructor. Dont be afraid to bore on in, why
why
why. If you do not get answers that you understand, find another expert. Make sure that the advice makes sense in terms that you understand. When it does, buy the gear and never look back.
With all that said, I really cant advise you until you define the diving you want to use your new suit for, but here are some thoughts:
Crushed, laminate and vulcanized suits have no inherent insulative properties so they are totally depended upon underwear and gas trapped in the suit for insulation. As you descend you add gas to the suit and that keeps both buoyancy and thermal characterizes constant.
Uncrushed neoprene (and please understand that there is a HUGE difference between the neoprene many suit manufacturers use and quality Rubatex in terms of compression) will crush with depth, but not 1/2 at 33 foot, 1/4 at 99 ft, etc. As is does, you must introduce gas into the suit to maintain neutral buoyancy, just as with a membrane suit, and that keeps the insulation about the same.
Which is best? I don't really know. I've had Unisuits, Jetsuits, Vikings, DUIs, and a Polaris (Rubatex suit from a small Santa Cruz custom house) over the years. I currently have the Polaris which I prefer for shore diving, a Viking for polluted water (nothing else can really be disinfected) and a DUI that is a joy for boat diving. I use an old set of Unisuit woolies under the Polaris and a ripstop/holowfill/synthetic pile (the blue and gray stuff) set of Viking underwear under the Viking and DUI.
For protection from the rocks the Polaris is the best, for minimum drag while swimming the Viking wins hands down, for ease of in and out, the DUI gets the nod. For ease of repair, it's the Viking. There is one thing that I have in common on all three suits: SiTec wrist rings (which I use with wrist seals) and SiTec neckseal/dogcollar/dryhood system. I can easily introduce air into the glove by raising my hand and wiggling my fingers (this lets some air past the latex wrist seal) and I can get air out by careful burping. The neckseal system allows me to throw away a torn neckseal and have a new one in place in seconds, and the dry hood adds a lot of warmth.
