flyingguy, Doha is certainly a safe enough place for families (as far as anyone can gather so far), plenty of guys I know are very happy with having their families here. But living is not as cheap as no sponsor makes out, although the petrol costs are indeed a plus!
Food is definitely not 20% cheaper than the UK - I don't know where he shops and eats out but I wish he'd spread the word. Some indian/thai/local restaurants are excellent and very cheap, but western ones are definitely not, any bottle of vino will cost you a minimum £15 if you are in one that serves it (hotels only), but family ones are reasonably priced.
Supermarkets are getting very expensive though if you want any European items. OK, there's the shipping costs, but profiteering seems to be taking place on a large scale - as everywhere in Doha. They all want a piece of your tax-free cash.
Still, you can save more than you would in Europe as an FO, and if you have (very) thick skin and can hack the company mentality then the place is pleasant enough to live in.