Neoprene vs Membrane.
Neoprene :-
Neoprene is thermally much better than membrane, most of the year you won't need an undersuit.
Neoprene is buoyant and you may need more lead, depending on what you wear underneath and whether it is 'compressed'.
Non compressed neoprene can cause buoyancy problems as it expands as you ascend, whereas compressed won't vary much in thickness.
Neoprene is usually more expensive.
Neoprene can be too warm in the summer before you get into the water, beware dehydration.
Neoprene is more flexible.
Membrane :-
You will always need a thermal undersuit except in warmer waters, used mine in the Red Sea in Feb last year as the wind chill is coooool.
Neutrally buoyant so no problems from the suit during ascents/descents.
Not very flexible material.
Cheaper.
Tough.
Both are tough but modern membrane materials are extremely tough.
If you feel the cold you will be better off with a neoprene.
A good fitting drysuit is most important, one with enough room to move without too much restriction. Too much room inside and air will migrate to those areas and cause probelms. The lower legs and feet are the most important areas to fit well, air migration to that area will cause problems.
Once you are used to drysuits you can use anything.
Personally I like the Aquion Extreme front loader membrane suit or an O'Three neoprene. I use the Aquion and found it comfortable and tough and a true self-donning suit. Same sort of money as an O'Three.
I also have an ND Cortex which works well and Otter do a cheap Neoprene for £395 which I have been contemplating, purely because I wear them out so quickly (18 months, roughly 5-600 dives).
Use a good fitting drysuit properly and it will give you good service and easy diving. Main problems are overweighting or using BCD instead of drysuit for buoyancy, if you have to put air in both you are overweighted.
