We've been thinking about getting one. We had one 4 years back when I was training and working long hours (though on reflection my hours are as long now!), but unfortunately she left after 2 months due to health problems. she was great: of the old school and did a great job (skirting boards etc.) We tried someone else afterwards who only came for one visit.
I've recently picked up a card from the PO for a cleaning lady and don't know whether to go for it. My reluctance is due to said person being allowed in our home when neither of us is here - she'd have to either have a key or have one left out for her. there is an agency a mile away but they quoted about £17 an hour, which I think is hellish expensive.