Maneuverability
If you've never been in a drysuit and want to use it for hunting I'd recommend that you do several dives on rentals or demo drysuits. Maneuverability characteristics are quite different. I haven't done catfish hunting, but for the tropical saltwater hunting I used to do, maneuverability was important. e.g. Depending on the drysuit you may find it is not as easy to go inverted (or more accurately, recover from an inverted position). Also, you have a dump valve to be mindful because certain positions will trigger the dump valve, if you dive it opened, and if you don't, you have to get into position and manually dump it for buoyancy control. Another thing to consider is that certain seals (more neoprene than latex) will leak if you twist your neck or wrists too much.
Durability and Abrasion Resistance
In spite of the popularity of shell suits in recreational circles, neoprene drysuits remain very popular among commercial and fish farm divers around this vicinity -- Canadian west coast. In order to further increase durability they are available with external laminate options like "Duratex", "Diamond Tuff", "Gator Hide", or even kevlar. Bare, Seatux, Oceaner, and Brooks are some of the local drysuit manufacturers that offer this type of neoprene models. IMHO these neoprene suits are generally superior to shell suits in terms of durability, particularly if they have one of these special outer laminates. One more thing to consider in terms of durability is neoprene seals vs latex seals. Latex can be more comfortable but neoprene seals are harder to rip.
Thermal Properties and Compression
There is no question that neoprene will compress with depth. It is only logical to assume that you will feel colder when neoprene is compressed thinner. From what I've personally experienced, that is not necessarily the case. For instance -- two dives I did in the same exact location:
Dive 1 = Jul 11, 09. 11:44am. Max depth 115'. Run time 57 mins. Water temp 50F. Air temp 72F. Whites Fusion, t-shirt shorts, Whites MK2 full length undergarment, Whites thermal socks.
Dive 2 = Sept 26, 09. 7:02pm. Max depth 145'. Run time 80 mins. Water temp 50F. Air temp 63F. Brooks Sealsuit 7mm neoprene, thin long sleeve polyester fleece shirt, thin cotton/polyester fleece sweat pants, acrylic/spandex thermal socks.
On both dives I was using the same Pinnacle 4mm merino lined wet gloves. I felt warmer on the deeper, longer, night dive. I realize that my own subjective conclusions based on only two dives are hardly incontrovertible facts universally applicable. But that is just my point -- mileage will vary from individual to individual, as well as dive to dive. Try them out for yourself, personally experience and find out what is best for you.
