Hello,
I recently purchased a freedive suit and did some research. Now, please understand that I am not an expert, and I may have misunderstood the experts, so please verify the following:
Nylon exterior is for situations where you are going to be in rough water or contact rocks and coral. The nylon exterior protects the neoprene from abrasions. Nylon is also recommended as a first freediving suit because of durability (and they tend to be less expensive).
The smooth suits offers less resistance to the flow of water as you dive, more warmth, and in some cases - wind resistance. Smooth exterior is recommended for experienced divers who are less likely to tear a suit when putting it on or when diving among rocks (this is not me). Roger Yazbeck @picassoamerica.com was extremely helpful to me.
A true story to explain why I am GLAD I bought the Nylon suit:
(to verify the following, you will need to go diving with me)
Last Sunday I decided to dive Carmel California. I arrived just after sunrise to find a stiff offshore breeze kicking up the swells and fog threatening to overpower the offshore breeze and cloud up the dive spot. I knew I could drive around the point and get out of the wind, swell and fog, so I set out for a spot I have never been before. Suited up at tthe new spot and ready for hours of diving 30-40 foot water, I noted that there were hundreds of rounded cobblestone type rocks ranging from tennis ball to shipping land buoy size. Thinking I was pretty clever, I decided to enter the water with my fins in my hand to make it easier to walk among the stones. The waves were small and I had no difficulty entering the water and pulling myself over the plants and rocks to water about 10' deep where I I placed the left fin in my armpit and attempted to don the right. While floating in this modified fetal position, I began to slowly rotate to one side. Having one foot in my fin (heel cup not yet on) I corrected my position and watched as my left fin disappeared into sea grass about 5' thick (until I watched my fin going bye-bye, I thought it was about 2' thick). I pulled right fin off and retrieved the left before the current could whisk it away. Deciding this operation will be easier closer to shore where I could stand, I worked my way back inside to a nice tall rock where I could set my left fin so I don't drop it again (those of you who have been here and never admitted it, or have been around know the next part). I get the right fin on (recall the 5' thick seagrass? thought so, well it goew here also and I am still cleaning it out of that fin) and just before I turn to get the left one, a series of waves comes through and washes over the rock taking the left fin with it. Plants and sand clouding the water, I search for lefty with wholy unsatisfactory results. Standing on a submerged slippery rock, I see my left fin being sucked out in a deep channel between some rocks. Using a combination of long forgotten wrestling, rock climbing, and Three Stooges moves, I dove over the rocks (buoy sized), into to the offending channel grabbing the now offensive left fin and curse the voracious seagrass threatening to swallow all, not unlike the blackhole theory. Flailing back to shore with the right fin now also in hand, I have a moment of extreme self-consciousness. I reach a rock well above the water and scan the cliff, where I see a 60+ year old woman sitting on a bench (grandstand?) smiling at me while she shares her breakfast with her dog. This is too much and I burst out laughing at myself. Speaking loud enough for the dog to hear, I proclaim: "Lesson #1, ALWAYS put on your fins prior to entering the water... Lesson #2, time to lose this gut so I can actually put my fins ON." I promptly drove to the rough, windy, foggy side of the point and had a great series of dives before going home. Needless to say, I have been less tired after diving twice as long, but hey, entertaining is hard work!
The suit does not need repair, but now you know you need to talk to someone else :]