Look, there's nearly nothing worse than spending a winter on the trainer. I bought these looking for the ultimate in deep-winter warmth, and they don't disappoint.
Fitting into these is a bit...tedious, which is to say it something like a snake wriggling back into an old skin. With that said, entirely worth it. Once they're on, they fit like a glove, which is essential to maintaining the appropriate temperatures.
I've worn these down into single digit temperatures with corresponding wind chills, and no problems. For reference, I coupled these with a rapha winter gilet, two base layers and a jersey, and I was happier than I've ever been in cold weather conditions.
The bibs provide excellent back coverage, and the fabrics do a remarkable job maintaining the appropriate level of heat -- too often are garments either too hot to enjoy comfortably, or just not warm enough. These are that perfect fabric you wish existed.
One note: be careful sliding these on your legs. I did occasion to hear some stitching rip sounds when I pushed my leg into a stirrup too fast without moving the fabric up north into appropriate leg position. I don't want to buy another set (you only need one set!), so I'm more careful now.
All in all, these are THE deepwinter tights to get you through.
One other point of interest: the chamois is fantastic. Something about deep winter cycling makes me believe, at least intellectually, that I need something *more* in the padding department, and these fit the bill. The chamois moves with the body fluidly, and I've ridden at least one 110 mile century with about 9k in climbing with no issues.