I hope that you're not tempted to buy by mail or on E-Bay or the like. A personal examination and test of fit for you is, I think, essential. Go for one of the major, well-known manufacturers, if you can. They have made it big because their products are sound. When you find a suit - first things first, make sure it's watertight. You will need to carefully tie the neck seal shut and place soda bottles or something of a suitable size in the wrist seals. Then use a low-pressure inflator to blow up the suit. Major holes, tears will make themselves immediately apparent. Smaller ones may take some time, or you may have to ask if you can 'dunk' the suit in a bath or tub to check for bubbles. If it's watertight, check out the dump valve (usually left bicep or wrist area) and inspect the suit for heavy wear. Have a really good look at the zip area. This is a vital seal. Be cautious about any patches or repairs if they don't look professionally done. Finally, before you part with the bucks, make absolutely sure that the suit is a good fit (remember you will be wearing insulating undergarments when you dive it). A good drysuit should be snug, but not tight. If you have a choice, go for a suit with self-entry features (a zip that runs diagonally across the chest). This will make life easier for you in the long run. Good luck - let us know what you finish up with.