Old thread, but since I booked Maid2Clean in part because of the discussion here, I thought I'd give my experience.
I booked Maid2Clean a few months ago to do a deep clean of a flat I had just moved into in Leicestershire. There was almost no furniture in the flat and it was in reasonable condition, so it was not a big job. But I decided to book a cleaner in for a full day to allow for a thorough cleaning.
The cleaner worked in slow motion, more concerned with filling the hours than getting the job done. She spent perhaps two hours on the kitchenette alone, even though there was very little to clean. She showed no initiative and I had to point out all kinds of things she had missed. After she left, I noticed she had cleaned nearly nothing above her eye level, even though I provided a step ladder -- for instance, window sills were filled with dead bugs, cobwebs and twigs. The closer I looked, the more dirt I found. She had apparently used little elbow grease and largely just moved and smudged the dirt around.
Maid2Clean appears to be little more than a dispatcher for freelance cleaners, so it's apparently luck of the draw whether you get a competent one. Even as a dispatcher they do a poor job, however, as it took me several emails and phone calls even to make a booking -- I had to chase them; they didn't call me back. Amazing they stay in business.