As Destroyer stated Stonehenge and Abyss were already in Flagships release, and yea Destroyer this version is free to play.
I downloaded this version of Hellgate London 2 days ago, setup went smooth on windows7 64bit, I used the main download and not the torrent.
While the graphics have taken a turn for the worst the gameplay is fast and smooth, some people talk about the 1fps bug in this version, but i can remember people having that bug online with Flagships version too, anyway i have not had any bugs yet.
I got to act3 today i had to purchase an act3 pass which i payed for with ingame pallidium (spelling), i had leveled 2 toons to 17 which gave me about 500k, the pass cost 450k but this is account based so all your toons can go there now.
I am enjoying playing hgl again, the main reason i got this version is to play with others in the wilds abyss etc like i used to do with the old version. No doubt there are new end game instances too but i bet you need to gear first for them.
From what i have played i can say that this version is better than the original hgl.