Highly recommended!
A wonderful location (close to everything), 10 steps from the Russell Square underground station, the apartment has everything you need.
We were 10 people that stayed for 5 nights (6 adults and 4 kids under the age of five). Had enough beds, a great kitchen to cook and Mark was helpful with any issue that came up (and there weren't many as everything was well organized).
If you are part of a family that enjoys walking all day and visiting London's attractions, be in a centralized location, but come back for a home made dinner, put the kids to sleep and go out again (adults only, in turns of course), this is the perfect place for you.