So I got my footbeds at Mel Cotton's in San Jose (on San Carlos and Race street) and had the chance to try them for a week in Tahoe. Overall I would recommend the place, and my experience was positive, although I am not really sure what to expect, and have no basis for comparison with the way other places do them.
Mel Cottons makes instaprint footbeds, and uses a what they call 'weight-less' system, where you put your feet (while sitting) on a silicon pad that molds to them. It is not entirely weightless since you do put some weight on your feet, but they claim, and I agree, that it is superior to the systems where you stand on the molding surface.
The whole process took around half an hour, the guy did some measurements to my feet, and then took the mold. I went back a couple of days after that to pick up the footbeds. The reason I got them was that I felt I had some trouble edging the left ski well, which was apparent when skiing on one ski. The footbeds seem to have fixed that problem, and provide an overall more comfortable fit. The first couple of days I skied with them it was somewhat painful when I buckled my boots tight, but I gradually found the right settings for my buckles, and everything works great now.
I can't really say I experienced any dramatic changes in my skiing though like some people on this board have. I do feel my skiing has improved but it's hard to tell how much of it is due to the footbeds, and how much is due to being able to ski a few days in a row. One thing I can definitely attribute to the footbeds though is that I feel much more stable when schussing at high speeds. I also don't feel any asymmetry between right and left turns and I think the footbeds are a factor there too.
It would be interesting to put the stock footbeds and try a couple of runs, but I don't really have the time and patience to do those comparisons since the end of the season is approaching and I want to get the most out of every minute on the slopes.