The Snug is a fine place to stay while visiting London. It's very adequate in terms of amenities - though as the name suggests, things are snug at the Snug, and includes a small refrigerator, oven, toaster, hot plates, iron, etc.
As a result, staying at the Snug can be quite comfortable. In addition, the host is very nice and kind. She (we didn't get to meet Simon) was very helpful, and willing to provide suggestions, etc.
The nearest grocery store (Tesco) is a walk away, and Crystal Palace is also a short a bus ride away. IT has numerous dining options that were completely adequate for us on the first evening.
Other than that, you're probably aware of two defining features of the Snug: (a) it's snug, i.e., too small for parties of more than 2 people (unless the third is an infant or small child who won't go stir-crazy), and (b) it's not in central London - usually takes 30-45 min to London Victoria station.
We had a great and relaxing time in London while staying at the Snug, and would recommend it without reservation.