I had to order a size up because of the width.  I  ordered a size up so that the width fit, but in return the length is so far off it became uncomfortable.  It works out for lounging around, but I'd say they aren't practical at all for walking, or camping as advertised.

Warmth and comfort (assuming it actually fit right) would be a 5 out of 5.  I really haven't come across another pair of slippers that actually warm you up and keep the heat insulated.

As far as sizing goes I say 1 out of 5.  I really want to like them, but the fact they ignored the entire population of wide feet I just cant give it the rating I'd like to.

I am interested in checking out other omni-heat products such as their jackets and gloves.