I wear Meindl GTX Burma's, which have the MFS, and they're just superb - Basically you lace them up at the start of your walk, then again after half an hour or so - once the foam gets warm it moulds to the shape of your ankles, and the laces need to be re-tightened . . .
I've been wearing Meindl's for 10 years or more now, and I've never had any problems with any of the 3 or 4 pairs I've owned in that time - They're comfortable straight from the box, need no breaking in, and perform well - great pieces of kit . . . .