I've been using Intuition liners for five years, and they are fantastic. I use the race liner, which is thinner and higher density than the regular liner, but even so they are the most comfortable things I have ever put on my feet (with low volume Lange race shells, no less).
I've had problems getting boots custom fit all my life due to having wide feet, a full size difference between my feet, and having a very high arch. No matter how much work the bootfitter did on the shell and liner, in addition to having custom footbeds, I was typically in agony after 10 minutes and my first motion after skiing into a lift line was to lean down and undo all my buckles. With the Intuition liners, once the shells are punched out in the appropriate places (sides and the toe box and heal for my large foot), it is like heaven.
I don't use my custom footbeds anymore. When I had the liners made, the bootfitter put a generic Superfeet footbed into the shell first, then put in the liner over top of it. This helped force the foam up into the bottom of my foot and arch area so that the liner became a very comfortable footbed itself. It works amazingly well.
In addition to being the warmest liner I have ever used, the other thing I like is that the liners are incredibly light. Combined with a light race shell like the Lange, the combination feels almost like you have nothing on your feet compared to other boots, and you get fantastic sensitivity to the snow. I can't say enough good things about them.