Companies like Strolz offer foam boots and Nordica and Head offer foam linears so there must be people using them. But who are they and how pleased are they?
I just got my Strolz boots foamed this year, since my old liners were packed out. (I'd bought them with regular liners, which you can do here in the US.)
The fit is significantly tighter. *Too* tight on one side of one foot, in fact; I need to take them in for an adjustment. Only really bothers me towards the end of the day, or if I have to walk around in the boots a lot. It was bothering me more at high altitude in Europe, and I haven't gotten back out to the shop since I got back.
The Intuition liners seem to be the hot thing these days. Haven't tried them, but I'd guess they give you most of the fit advantage at a fraction of the price. If I didn't already have the Strolz setup I might have gone that route myself, or at least tried it for a season before springing for the custom foam.