The Seaskin is made-to-measure, so the fit is, well, custom. Mine seems to fit pretty much perfectly. I expect it's down to how well you follow the instructions to take the measurements that you provide. Thus, I cannot compare it to the fit of an Ursuit or 4E. Other than one of my fellow instructors at my shop got a 4E Argonaut, fitted using the Biomap process and his seems to fit him perfectly as well. The only thing I haven't tried yet, to really confirm the fit, is dive it with the 250gr made-to-measure undergarment I got with it. I tried it on in my living room and the fit felt good, but I need to get in the water and confirm I can still reach my tank valves on my doubles even with all that on underneath.