Drysuit valves come in two basic flavours, SiTech and Poseidon, and by flavours, I mean connection types. They are not mutually compatible, and they affect a lot of the equipment that you’ll need to rent or purchase. SiTech style valves are the “standard” valve connections found on most scuba equipment, especially in the recreational world. Poseidon valves are less popular in the recreational world, but are effectively the standard for commercial diving. When you pick a suit, make sure that the valve types are the right ones for your octopus and hoses, or vice versa. Another important point is that these valves can have any number of company logos on top (Apeks, Mares, DUI etc…), so be sure to ask about them when you’re making any purchases or rentals to ensure compatibility.
Drysuit seals come in two types and two variants. The types are neoprene and latex, and the variants are cuffed and uncuffed. Personally, I like the neoprene seals, they’re comfortable and easy to repair in the field or at home. They do have the disadvantage of not always providing the best seal though, and can seep if improperly fitted. Latex seals seldom if ever leak, but can be difficult to trim properly. They are also a complete replacement part if they become torn or damaged. On the cuffed/uncuffed front, this is determined by whether or not you use locking dry-glove gauntlets or wet gloves. Both have advantages and disadvantages depending on the type of diving that you’re doing and your own physical tolerances. With dry gauntlets, the most important thing, aside from ensuring they’re hole free, is to make sure the locking system works. I’m not the only diver who has seen a buddy’s dry-glove suddenly break free and rocket to the surface!
The key take aways from all of this are important to successful, safe, and comfortable diving. As a precaution, keep spares and repair materials in your save a dive kit, and maybe a few spare LP and HP hoses too. This can solve a lot of on the spot issues with valves and seals. Of course, the best plan is to make sure everything matches first!