Surely Neal Street must be one of the best locations to stay in London. If you can't actually walk a few blocks to reach where you want to go, the Covent Garden tube is just two blocks away, and from there you're off to everywhere! Although it's busy with tourists, especially on weekends, the location of Mattie's apartment, 3 levels up with the bedroom at the back, means there are no problems getting a good night's sleep in a very comfy bed.
There is no lift, so if you have mobility issues, it may not be right for you, but we found we were much fitter by the end of our stay! Location trumped everything for us. However, I should also mention that everything we could possibly need was provided, the appliances all worked beautifully and we were very comfortable.
Mattie met us for check-in and was very warm and helpful, going the extra mile by helping haul our suitcases up the stairs. I was very impressed.
I would say, if you're looking for somewhere quiet but close to everything, you should try to stay here. You won't regret it.