I enjoyed my meal at Charlie's, and I think I can explain the way the Yelp reviews careen between 1's and 5's.
This place is OLD and old-style. It opened in 1952 but might as well be from the 1930s. It's teeny (just a counter and about a dozen stools), the menu is old-school (burgers, hot dogs, breakfast anytime), the food is all cooked to order, and the service is very friendly (the waitress calls you hon) . The down side of that is it's teeny (no restroom) the menu is old-style (no salads), it takes a while to get your food, and the waitress really slings the hash.
Your impression will be decided by what you honestly like and enjoy. If what you like (be honest now!) is swanky leasehold improvements and a waiter who crouches down to introduce talk about the chef's philosophy of locally sourced ingredients, walk you through the menu, and keeps checking if everything is done to your liking this is probably not the place for you.
If what you enjoy is a trip back in time, an almost antiquated menu and cooking methods (i.e., no delivered pillows of soup, or dozens of burgers sizzling on the grill waiting to be ordered), and a waitress who addresses you with a genuine human warmth, you'll love it.
I love hot dogs. I love places that are comfortably integrated in countless ways. I hate putting on airs. I loved the totally original decor. Was it the best, cheapest, most wonderful food ever? No. But it was a heck of a lot of fun. It reminded me of places I went with my dad 50 years ago or more.
(I would say it's not good for large groups as about 95 percent of the seating is counter stools.)