Since we are firing shots here....
I was doing OK until I went to NELSON to kill Dead Sea. I left from Fort Forlorn Hope and did the mission attacking from the East Ridge. Things went well.... Then when I return to camp Forlorn Hope or whatever, the NCR is attacking me immediately! I have hero status. I'm wearing NCR armor with a Ranger Beret. Boone is with me wearing the same. E-DE is metal.... So then I have this faction trying to kill me everywhere and there is nothing to do about it.... Legion and Khan gang attack me as well.... WTH? anyone else have weird glitches like this? I stopped playing the game and I'm waiting for another patch...
The Nelson quest is completely messed up. I generally avoid that whole area, because pretty much everyone who has mentioned doing that quest has had some sort of problem with it.
Forlorn hope is problematic as well. The head guy (who gives all the quests) has a bad habit of running off in a panic if so much as a bloat fly drifts too close to camp. Gets himself killed every time and fails all the quests associated with him.
I've not had any problems with factions attacking me, but I have had problems with factions who are supposed to be hostile being completely friendly. The Nelson quest is a good example. Both times I've taken the quest to liberate nelson, all of the legion act friendly towards me. One time when I completed the quest, legion and NCR were walking around together in town completely ignoring each other and non-hostile towards me.