JackBeagles has recently become my "go-to" for a weekend breakfast...it's like a Budweiser: always fills me up, and never lets me down.
I think it's always a good idea for a restaurant to keep a simple menu, execute a couple of items that you do really well, and don't overcomplicate or spread yourself too thin by trying to appease everyone. I think JBs really embraces this concept; they stick to a few basics, throw in a special or two, and keep the prices very reasonable.
As for the building, I've always just walked in the front door (push don't pull), and sat right at the bar. I'd probably just classify it more as "counter-service" than bar, as the kitchen is visible and somewhat open, and the service up front has always been efficient. Side note: I like that the coffee mugs are just a random assortment from local businesses that they probably got for free...It's kinda like a koozie, it's always better to collect them rather than buy them.
The inside has a real laid-back vibe, and you'll usually catch a couple of people at the bar completing a crossword puzzle, or just there sipping on some coffee. Striking up conversations with others is typically easy & comfortable.
As mentioned before, I've only been for breakfast---but I'll definitely check out their lunch/dinner options if I'm ever bar hopping around NoDa some night.