Syria rebels overtake strategic base in south
"The south is the last major stronghold of the mainstream, anti-Assad opposition, who have been weakened elsewhere by the expansion of the ultra-hardline Islamic State group in the east and north, and gains by the Nusra Front in the northwest.
However, Nusra is fighting in the south alongside the Western-backed groups, who have proved more united there than in other parts of Syria."
Here we see that Nusra and ISIS are not the same thing (though there was a worrying report that Nusra has ordered Ansar al-Islam (FSA) in the Eastern Ghouta to disarm), and that there are moderate Syrians wherever they receive some support.