Thatcher's fundamental achievements - while doing plenty of harm - do deserve respect. Fact of the matter is that the Unions needed quashing, and there was no reason whatsoever (and plenty of reasons against) keeping the bulk of industry nationalised. Thatcher deserves credit for bringing these reforms through.
Her third term, though, was an absolute disaster.
So I think it's going waay too far to say she's the second greatest leader we've ever had (Disraeli? Gladstone? Lloyd George?), and even her supporters must admit the damage several of her policies inflicted, she does certainly deserve respect for the basic acheivements.