I had a great stay at Maria's. The room is a good size and comfortable. It is a bit out of central London, but with awesome transit options and very easy to get to and from sightseeing. I had spent extra on my flight and activities, and the value of Maria's listing was wonderful.
She is a most gracious host and very communicative, with lots of tips, especially on getting around.
If you're traveling to London and don't need to be right downtown, I highly recommend saving some money on accommodations with this listing, and splurging on your other activities!