I stayed at Ari's apartment for a full week and I really can't imagine a better place to stay. As several other reviews mentioned, it is much bigger in reality than it looks in the pictures, which are extremely accurate. It is only about a ten minute walk to either the South Kensington or Sloan Square Underground stations. There is plenty of food nearby, including a Sainsbury's Local that is a three minute walk away and open until 11 PM.
What struck me most about Ari's place was how quiet it was. Not only did I almost never hear anyone in the neighboring apartments, but there was very little street noise after hours.
Ari was a very helpful and communicative host. He contacted me via WhatsApp before I arrived and we had a very pleasant conversation. When I got to the apartment he had detailed instructions typed up of do's and don't's regarding pretty much any question I could have, from how to use the washer to recommendations for places to eat. He really made the stay effortless and I appreciated his thoughtfulness.
I hope on my next trip to London, I'm able to stay at Ari's place again. It would be hard to find a better one, especially at the price.