" My advice would be to not "live" off of these products if you are a vegetarian"
I do have to say that these "meats" do taste a whole lot like the real thing. I even fed breaded faux chicken patties several times to my non-vegetarian friends and they did not even know the difference. I remember them usually being a bit pricey, but I was a vegetarian who was used to purchasing only grains, vegetables and fruits, after all. Compared to real, quality meats, the prices of the faux meats are comparable.
Now, on to the real question. Are they healthy? Well, if you look at the list of ingredients, you will see the names of many chemicals on the labels of many of these products. Strike one. They are made usually made with soy, but very processed, altered soy. Strike two. Many of these products also contain lots of sodium, but so do most non-vegetarian food items, so I will not give them a strike for that.
My advice would be to not "live" off of these products if you are a vegetarian, but to only eat them every once in a while for a treat, or when you get a strong craving for a "meat" product. Everything is fine in moderation, but if you are a vegetarian for health reasons, I would not eat a diet that consists of these "meat" products as a staple food.