It's delicious, but it's really just garbage branded as healthy. People think it's healthy based on the perception that it's healthier than McDonalds, KFC etc, which it may or may not be, but that's really the food equivalent of smoking low-tar cigarettes.
The reality of subway is:
Lots of bread - wheat makes most people fat
Shitty processed meat
High calorie (or sugary) dressings
Plenty of veges, sure, but you don't have to go to subway to get that.
All good if you're in to junk food, I just find the "healthy" branding hilarious.