I've owned a bunch of different drysuits over the years. My thoughts, in no particular order of importance (except for the first one) ...
- The most critical consideration in the purchase of a drysuit is fit ... it must fit you properly. Made-to-measure suits are a crapshoot ... my experience is that companies get it right about 50% of the time. This has mostly to do with who's doing the measuring. IF you decide on a DUI, wait till a DOG Days event comes around and get someone from DUI to measure you for the suit ... they know what they're doing.
- Customer service ... some are better at it than others. I had really good experiences with DUI, although that's because I tend to be hard on suits, and my TLS350 was going back rather more often than I'd like. They took very good care of me, though, and I loved that suit. Bare's customer service left something to be desired ... they always took care of me, eventually ... but I could count on my suit being gone for 5-7 weeks before I'd get it back.
- Compressed (or crushed ... they're slightly different) neoprene doesn't "lose" buoyancy at depth. That's the whole point of compressing the neoprene before it goes into making the suit. The biggest disadvantage to this type of suit is it doesn't travel well ... it's heavy and takes too long to dry for the flight home. They are generally warmer and more durable than a trilam, however.
- Boot styles can be a factor ... some folks love rock boots, others despise them. Different manufacturers offer different options for built-in boots. Heavier boots are better for climbing over rocks on shore entries, but provide less flexibility and "feedback" for the more subtle kicks that tech divers tend to use. Lighter boots allow better fin control, but don't offer much of a buffer between your feet and the ground on shore entries. Pick your poison.
- If you go with a DUI suit, consider getting somebody else's rock boot ... DUI's boots are more expensive and less durable than some other alternatives. I personally like the Bare boots ... and Whites used to make one I really liked (Altera), but discontinued it for some reason.
- Lightweight suits like the DUI TLS350 and the Santi eMotion are generally very comfortable and easy to don/doff, but tend to be less durable than heavier suits ... they do travel very well due to their light weight and the fact that they dry rather quickly.
- Pee valve ... if you're going into tech diving, you'll want one. Same applies for pockets.
- Front zip suits are easier to don/doff ... back-zip suits will generally provide a better fit.
- Your choice of undergarment is at least as important as your choice of suit. It may behoove you to consider two or more undergarments, if you plan to use the suit in different water temperatures.
- Investigate seal choices. Neoprene seals are more durable, and more expensive ... and harder to replace. If you're going to use drygloves, then get latex or silicone seals, at least on the wrists. Zip seals (DUI) offer some conveniences, but consider that you'll have a neck ring to deal with, that replacement seals are very expensive, and that your drygloves are basically permanently attached to the suit. Some folks love 'em, others hate 'em. I ordered one suit with them, thinking it's a darn good idea for an instructor ... and hated them. Ended up sending the suit in and asking them to replace the zip seals with regular latex ones.
- Speaking of drygloves ... investigate different ring choices. About a third of the people I know who use them didn't like the ones they purchased the first time, and ended up buying twice. My favorites for function, ease of installation, price, and being leak-free are the Viking bayonet style rings ... but they're smallish diameter and not suitable for people with wide hands.
... Bob (Grateful Diver)