It's charming, it's delicious and it provides great food much, much cheaper than the overpriced fare offered around it. In particular, it provides a greater variety and more reasonably priced food offering for breakfast if you are staying in a hotel.
When I'm in New York I usually stay around 42nd Street and often at the Grand Hyatt a few doors down from Grand Central, just across the road. Skip the hotel breakfast and head here for perfect eggs benedict or whichever takes your fancy. I have done it many times. If you are back around there for lunch - I loved the delicicous shrimpscargots and the maine lobster roll. And dinner? Well I've not had dinner there yet, but I'm certainly tempted!
Without hesitation - a great spot. Do it!