Appin is a..house. Run by a Scottish family and located just 3 kilometres from the central shopping street (known as The Royal Mile), it is ideal for those with small budgets. Like with most family-owned hotels, one mustn't have very high expectations.
You will get a clean room and I'd expect that it'd be sufficiently large - my friend and I booked a twin room, but were given a family room which was HUGE! That said the bathroom was tiny and a bit disappointing.
The owner is very helpful and spending ten minutes with him will help you polish your itinerary. He'll tell you about bus routes and how to get around, what to visit when, and also a bit of history if you are patient.
Morning breakfast is not spectacular but serves its purpose. For lunch and dinner, there are numerous restaurants (and hotels, other B&Bs, etc.) along the road connecting Appin House with The Royal Mile. (Tip: arab cuisine abounds, and its quite good too).
In summary, Appin House is a very nice, homely setup that is easy on the wallet. You'll come away feeling you haven't strayed far from home.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC