I hired a local firm that had good reviews. They failed to turn up on the agreed day. When I chased them over the phone they made an excuse and said they would come the following afternoon at 3pm. Instead they turned up at 12 o'clock just as I was having lunch.
Three women turned up, only one of them spoke (broken) English. One went upstairs with a vacuum, damp mop and dust cloth. She was up there for five minutes before coming downstairs.
I had to ask the woman who was cleaning the living room and downstairs bedroom to dust the skirting boards and windowsills, she did not move any furniture. She flicked a duster, then ran the same damp mop over the floor that had already been used in the two bedrooms upstairs without being rinsed.
The lady who did the kitchen was a lot more exacting, she polished the kettle and toaster, pulled everything out of the cupboards, and cleaned every shelf before putting the stuff back (not always in the same place). She even got the step ladder so she could clean the top of the cabinets. She very proudly came to me with 3 empty boxes of laundry powder (for whites, non bio and all in one) asking where I recycled my cardboard, because she had done me the favour of tipping all three boxes into the giant, almost empty box of Daz that was also under the kitchen sink. Of course she couldn't read English and therefor saw no reason why I would have 4 different packets of laundry detergent taking up space.
Whoever did the bathroom was also very enthusiastic. She cleaned the shower drain really well, which I was happy about because the main reason I got them in was that I can no longer bend down far enough to clean the drain myself. She scrubbed everything and then either used the shower to rinse the sink and toilet or sploshed whole buckets of water about the place. I know because I had to interrupt her to use the toilet and the floor was swimming in water.
After they had gone I took a pair of socks out of the plastic chest of drawers next to the toilet where my bras, knickers and socks each have their own drawer, with the top drawer holding make up. The socks were sopping wet. Further investigation revealed that each drawer had an inch or two of water in the bottom, so all the underwear was sodden. The make up seemed to have been washed but that drawer had been dried. Either she didn't check the lower drawers, or she did and decided all those wet undies were too daunting to cope with.
I was glad that I found the sodden underwear quickly and was able to wash and dry everything that same evening. For months afterwards, when I did a load of laundry using the pot luck who the fuck knows what it is box of detergent I was chortling about that afternoon, and lady who wet my drawers for me.
When I managed to navigate the stairs and check those bedrooms they did look tidy enough, the collection of dead flies was gone from the windowsill and the surfaces looked dust free. When I clean I use long handled dusters and long handled wet mops to clean the places that are hard to reach, and I rinse them often and change the water in the rinse bucket when it starts to look dirty. I also either steam clean or wet mop the hard floors, rinsing the mops and changing the water. Swishing over every hard floor in 7 rooms without rinsing or changing the mop head doesn't really make me feel that the floors are clean afterwards, even if I can't see any dirt.
So now I tip drain cleaner down the shower drain, and hobble around doing my own deep cleaning. I had expected them to clean the windows, at least indoors, that seemed to be included in most "deep clean" services, but as mentioned above I had to ask for the skirting boards and window sills to be wiped down.
My best advice would be to have a written list of everything you want cleaning, and ask them to quote for the job so that you aren't disappointed afterwards. Also keep an eye on your knicker drawer and laundry detergent!