Pros - the location is excellent! plenty of clean linens and towels. great restaurants and tube stop nearby. easy walking distance to most sights. relatively quiet at night.
Cons - there is no A/C, so we were miserable during the heat wave and got no sleep. host was unwilling to modify the reservation so we just had to suffer through it. also, unit could use some basic improvements (ex. there were no trash cans so we put plastic bags throughout the house, and there was a straightened wire hanger to pull down the window shades.). small improvements would go a long way to making the unit more livable.
overall, I think it's a good unit (weather permitting). if you don't mind working with the minor discomforts, the location is optimal for central London.