To stay with a family or in a hostel

I am currently studying English in London and staying in a hostel. This is getting expensive and my school have recommended that I stay with a host family. They recommend a company http://www.londonhomestays.com/. I have never stayed in a homestay and have no idea what it would be like (what can I expect from a family in London?). Does anyone have any experience of staying with a host family or even better have you used this company?

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