I previously owned a Mares Isotherm. It worked very well at preventing water flushing through the suit. In fact, my torso would usually remain fairly dry after the dive. However, the neoprene compressed too much at depth, to keep me warm. Diving in California where the water temperature averages 47-55 all year long, I was very cold at 60 feet. At 80-120 feet, I was right down miserable. I will say that I don't tolerate the cold very well. I'm 5'5 and weiged about 125lbs at that time, which put me just south of single digit body fat percentage.
If you can tolerate the cold better than I can, this suit may actually work. I did find the arms too short for my liking. The outer cuff of the arm was too short to go over the gauntlet of my glove. With a long lanyard, I didn't have any problems donning the suit absent any help.
C.