I've hired them in the past. When I was renting my house out to 4 shift workers up North I'd bring in a maid once a month to clean the house. She did an amazing job and only charged something like $120 for easily 8hrs of labour plus the cost of supplies. The 5 of us split the bill and it was a condition of being a tenant in my place.
After I got married and moved down South my wife and I would hire one once a quarter or so to deep clean the place. We were both working full time and couldn't be bothered to do more than clean the kitchen, do the laundry, vacuum and generally tidy the house up. 4 times a year was plenty enough to keep the place looking good as we are both generally pretty clean and tidy. Its more the dusting and bathrooms that neither of us like cleaning. Cost in Edmonton was around $250 - $300.
Now that I'm working full time and my wife is at home with the baby she does about 80% of the cleaning and I take care of the rest on weeknights after the baby is off to bed. We haven't hired a maid out for well over a year and our house is still looking good.
Finding a good one is tough. I lucked into a good one the first time in Fort Mac, but we went through at least a half a dozen before we found a good one in Edmonton. Never have had any issues with theft, but we always made sure to keep our valuables out of sight.