Treated myself to some Reed chillcheater pre-bent trousers a few weeks back.
These trousers are a sort of waterproof (allegedly breathable) stretchy plastic with a knit fabric inner surface. They are cut to be 'fitting right' when in a seated position.
High waist, particularly at the back.
Fit - slim on the legs and well shaped on waist and hips. The hips, for all sizes, are smaller than the waist. That is ideal for us Middle aged blokes, but not for many women and skinny guys. (Although I did lend them to my daughter, who is short with wide hips and they fitted her fine.)
I'm 170cm tall, 83kg and take a medium in jeans (86cm at the hips). A bit bigger around the tum.
The trousers fit me well, maybe a tad tight on the belly. Size Large.
Biggest worry for me was calves. I have big fat calves and was concerned I wouldn't get into the chillcheater - I do, but it is snug.
They are super comfortable when paddling. I had read that people found the material wouldn't slide on fibreglass, bit of a problem if you are trying to get some rotation. In my plastic ski they did stick a bit, but a quick scoop of water into the cockpit solved that.
Warmth? Not super super warm straight on, and I could feel a very slight windchill once they were wet. That didn't increase though (as it would if I'd been wearing my normal neoprene trousers).
With the neoprene trousers, they would start off warm but then get cold throughout the paddle. Big downside of ski paddling. The chillcheaters didn't get worse, and, crucially, once I got out they dried off during the portage home and kept me warm. Usually I absolutely freeze when getting out and walkign home; wet and windchill reduce me to a popsicle. Now the main concern when portaging is the PVC bondage gear look.
They are best 'dried' inside out, so that the fabric dries. Some water remains on the outer layer if dried inside out, but I've not found that to affect the warmth when wearing them.
I'm super happy with them. Should keep me going right through winter.