Last time I went, we ended up with some crunchy pasta. It was pretty gross.
Seriously though, the salt content is what I'm concerned about. Some of these freeze dried meals have just a load of salt. That can dehydrate you pretty bad, and make hiking pretty miserable. Also, stay away from the freeze dried breakfasts, bacon and eggs is not the same.
I tend to live off oatmeal, jerky, and Gorp, which is a type of trail mix, but I'm hoping to do a longer (two weeks or so) trip in the next year or so. Maybe I'll test a few of these MRE's out first.