The best burger I've had in a while was at a new addition to Glen Mills,
Five Guys Famous Burgers And Fries. Yeah, they're a chain, but when your chain's menu contains nothing but the following:
* Hamburger/Cheeseburger
* Hot Dog
* Grilled Cheese Sandwich
* Fries
* Soda
and you're in the process of adding 100+ locations, you're doing _something_ right.
The standard-issue cheeseburger is actually two patties, fresh-grilled well done, with American and your choice of toppings, big, juicy and messy. (Order the "Little" if you just want one.) A few nice touches make customer service pleasant: numbering burgers so that observant orderers know at a glance who in their party gets which, extra fries poured into every bag, peanuts in the shell in big containers for customers to munch on while they're waiting.
The decor is reasonably Spartan, but workable. Hours are until ten every night, even Sunday, making it an option when some other places have closed. My wife vouched for their hot dogs; I can vouch that the burgers are excellent, if potentially lethal in large quantities.
Cheeburger Cheeburger up in Frazer is also very nice and is a bit more full-featured (milkshakes, ice cream sodas and egg creams, eight kinds of cheese, wider menu, burgers up to 20 oz. before cooking), albeit a bit pricier.