Jimmy John's is nice for two reasons. They are pretty quick with making your food, and they have a low-carb option for all subs. I am a fan of the low carb option, because their one of the only places I can go for lunch and feel pretty satisfied about.
You can expect to drop between 8-10 bucks for an 8" sandwich meal. Their normal sandwiches are between $4 and $5. They have another option (between $5 and $6) for those who want a little more. If you pay for this option, expect to get double meat on, still, an 8" roll. If I remember correctly, making it a meal - which consists of a drink and either a whole pickle, chips or a cookie, and will cost you another $3.
I go here quite frequently for lunch, and their service is consistent. But I don't think that they are 4 star quality. Ultimately I rated them a 3 because of their price in relation to the size of the sub that you get. The sandwiches, I think, are good for lunch, but if I'm looking to have a good time, I wouldn't think of Jimmy Johns.
Also, the establishment is very clean. If you judge restaurants based on plumbing and cleanliness, I'm happy to announce that their place is very good.