O'Neill Men's Heat 4/3mm Back Zip Full Wetsuit for Surfing, Diving & Water Sports - Thermal Neoprene Suit with Comfort Fit & Durability

At 62 I have been a lifelong big wave surfer and a very strong long distance swimmer (2-3 miles per day 4-5 days/week). I am 5' 11'' tall, with a 31'' inseam, 38-40" waist, 46-47" chest, 52" around my shoulders, and 34" arms with only 13.5" biceps. I gained a lot of weight last year so 3 months ago I hooked up a harness in my pool and lost 20 lbs. swimming 1-3 miles per day in a NeoSport XSpan 3/2mm 2XXL full wetsuit. Now at 227 lbs I am aiming for about 205-210 lbs. by spring, but the water temp cooled to 68 degrees and the 3/2mm wetsuit was no longer sufficiently warm. Water was flushing in my neck and back quite a bit. I first layered a 1.5mm neoprene shirt under my 3/2mm wetsuit and got more warmth and less flushing, but arm flexibility was compromised.I decided to test the following 3 backzip wetsuits, and I really hoped the Hyperflex Voodoo would be my best choice for swimming in waters that might hit around 45 degrees;1. Hyperflex Voodoo 4/3mm XXL (LFS)2. O'Neill Epic 4/3mm XXL (GBS)3. O'Neill HEAT 4/3mm XXL (LFS)4. Quiksilver Syncro 5/4/3mm XXL (LFS)1. Hyperflex Voodoo 4/3mm XXL (LFS) My first shock was that the Voodoo was the hardest suit to put on by far (even over a thin lycra bodysuit) partly because of the non-slip fleece lining, but also because the arms were very tight on my skinny arms, and the suit was extremely tight around my shoulders. I had to have help pulling the floodgate over my head, and zipping the suit up. I am surprised I did not feel terribly choked by the floodgate or by the wetsuit neck when zipped up. Even though the tightness in the shoulders was stretching the neck piece a little, the neck piece still remained comfortably snug. Over all I felt like I was in a 5mm standard 50% flex neoprene wetsuit rather than a 100% stretch suit. This XXL was terribly restrictive of my shoulders and arms, and it felt like I feared a XXL-Short wetsuit might feel. I knew I'd be warm in this suit even in 45-50 degree water, and I'd have very little if any water flushing, but I could not imagine swimming 1/2 mile in this suit even after wearing it for over an hour indoors because if the lack of flexibility in the arms and shoulders.2. O'Neill Epic 4/3 mm XXL (GBS)AND3. O'Neill HEAT 4/3mm XXL-short (LFS)The 2 O'neill suits both went on extremely easily, which shocked me, and both fit me absolutely perfectly even thought the HEAT was a 2XL-Short and the Epic just an XXL. I purposely didn't stretch the Epic 4/3mm out when I put it on though it would have stretched out a bit in length in the legs if I needed it to. The HEAT fit me perfectly EVERYWHERE. The Neoprene in both suits was absolutely buttery, and both felt far more flexible than the Voodoo 4/3mm or than a NeoSport Xspan 5mm had felt a month earlier. The heat retention of the front panel in both suits was immediately evident. The Liquid Fluid Seal over all the seams on the HEAT 4/3mm suit were totally stretchy, and the added back heat panels convinced me I would be significantly warmer in the Heat 4/3mm than in the Epic 4/3mm suit with GBS seams. My only initial complaint with both O'neill suits was that the shape of the neck put a little pressure on the front of my throat - perhaps because my posture is not great and I stand with my head tilted forward a little (genetic trait) - but this issue became completely unnoticeable once I took the Heat 4/3mm and then the Epic 4/3mm into the water.4. Quiksilver Syncro 5/4/3mm XXL (LFS) - For a cold water suit, this would have been my second choice behind the O'neill HEAT with LFS. It went on easily even with the back floodgate, and I was able to zip it up without help from my wife. The Neoprene felt absolutely wonderful and stretchy, the seams were Liquid-Fluid Sealed and not just GBS seams, and the suit felt totally comfortable once zipped up. My arms and shoulders had easy and full range of motion and I knew I could swim miles warmly in this suit. My only issue and reason for spending $70 more on the O'neill HEAT was that the QuikSilver Syncro 2XL was at least 3 inches too long for me in the legs because I have shorter legs and a longer torso. The arms were also a little long for me, bulging a little around my biceps, but fitting snugly and sealing well at my wrists and all the way up my forearms. If I lose the 20 lbs. the O'neill HEAT XXLS will still fit me well, but the Quiksilver Syncro XXL would then become way too loose.My wife watched me try on and compare each suit, and since the O'neill HEAT 4/3mm obviously fit me the best and had the features I needed to swim long distances in cold water, after trying on the other suits I immediately made my decision and kept the O'neill HEAT 4/3mm suit on. I threw on some 5mm NeoSport booties, donned a swim cap and 3mm Neosport gloves, stepped down into a pool of 58 degree water (not feeling the slightest chill), hooked myself into the swimming harness and immediately went face first into the water to swim a mile. Only my cheeks were a little chilled at first. I felt NO water getting in through the neck, or the seams of my O'neill HEAT wetsuit. I felt No Chill at all !!! In fact, after about a quarter mile I pulled down on the front collar to let in a little water in to cool me down in the suit.After loving the O'Neill Heat, and looking at the recommended water temperature range of 45 degrees and up, I decided to try the O'Neill Epic 4/3mm GBS in the water. I jumped into the 58 degree water and felt a little more cooling water seeping in than with the HEAT, but I was warmed up from the mile swim so I decided to swim another 1/2 mile. I decided to keep the O'neill Heat 4/3mm for cold waters 45 degrees and up, the O'neill Epic 4/3mm for 56-57 degrees and up, and my Neosport XSpan 3/2mm would for waters 68 degrees and up.I hope this free personal testimony about these wetsuits helps you make your next decision about the wetsuit that is right for you.I’m 6’1” 165 lbs, waist 31”, broad shoulders, 15.5” neck and got the MT. The tall format fits me great but i might be a touch thin for the medium size as I get flushed a little down the back while duck diving or wiping out hard. This suit is nice though. It’s worth paying extra for the fluid seams. My friend bought an Epic around the same time and some seams were already coming apart. I surf this suit in northern CA 50-58 degree water all year round and never get cold. Actually some days when the weather is warm I wish I had a 3/2. Always wear boots and Sometimes throw some gloves on, never feel cold even when I get flushed wiping out. I like O’niell but since I can’t find a small tall size i might try Rip Curl medium tall to see if it fits better next time.Only had my first one a few months until a fin cut up the leg in a bad wipeout. I'm buying my second one soon. I'm 6' 5" 200 lbs, and a LT fit perfectly. The seals were all perfect, the key pocket was perfect. Pretty much everything you expect from an O'Neill wetsuit. No problems in winter swell in central CA. The one thing I noticed is that there is a lot of room in the crotch, which I've never had in a wetsuit before, and was extremely comfortable.Water gets stuck at the ankles and the only way to get it out is to get out of the water.It is warm and comfortable other than that.I have worn an 4/3mm XLS for a very long time. I tried this on at the surf store before buying it on Amazon. This wetsuit, pulls on my arms and hurts my back. The stitching in the shoulders is constraining and i feel i am constantly working against the wetsuit. After a sub par 2-3 foot session I came out of the water very fatigued due to the amount of work i had to perform with this wetsuit on. My last three wetsuits have been Rip Curl and I wanted to come back to O'neill, unfortunately this was not a good purchase. It feels alright on land but once in the water a different story. I bought it in the summer when the water was warm and surfing with it for the first time in the fall was very upsetting. I would like to return it ,but past the date.I have an extra large 3/2, it fits great! this suit 4/3 feels like a large not an Xrta-Large. The only reason I am returning, is that it is too small for a 225lb, male who stands 6'2"!Wish there were more like it. The whole zipperless and small opening wetsuit designs suck. The Heat has a regular back zip. Easy on. Easy off. So if you hate contorting to get in and out of your suits. This one is great. Quality construction. Stretchy and no leaks. Thank you O'neill. Now, please make us a real winter suit with a full chest zip like you used to!It's pretty warm but leaks in the back down the zipper. Wish I would have spent a little more and got a better suit. Doesn't have a batwing or flap which would make it a lot better so I have been wearing a short sleeve top under.