i have a dry suit, a 7 mil wetsuit and a mares isotherm, i have to say, that unless its cold on the surface or below 40 degrees in the water ,i will only use my semi dry. i love it, not too tight, water in it keeps you cool in warmer water, and warm in colder water. the thing i hate about wetsuits is while your in cold water you constantly have water circulating in and out, at least mine did, so always gettings cold water down the back, my wet suit was a pretty good fit too. im the kind of person that gets cold relatively easy and i dont like to be cold, and i love my semidry, a little pricey but well worth it. i usually have bottom times around 30-40 min and as long as your moving around they stay pretty warm. as a matter of fact, when i get to the surface and get ready to take my suit off, i pull back the ankle seal and the water is hot. hope this helps.