*Spoiler Alert*
So I decided to go with the NCR, and was really liking it until I was asked to kill the Brotherhood. They were the first faction in a Fallout game (Fo3,NV) that actually asked me to join. My character really believed in their principles, and I saw no justification for killing them. I tried to reason with the NCR chick to form a treaty, and she would have none of it. I visited Elder Cardin, and saw no dialogue options relating to it, so I decided I had to go a different route.
I decided that siding with an NCR genocide was as bad as the POTENTIAL genocide Yes Man would unleash against both the NCR and the Legion. I liked that the choice allowed me to kick the NCR out without destroying them, though the insolent general at the end got tossed over the dam for his shitty attitude ;)
I was very pleased with how things wrapped up, and I feel that the Yes Man route is a "good" ending. I think Obsidian did a surprisingly god job of allowing the player to form real relationships with the various groups, though I wish the Boomers, Khans, and Gun Runners had more prominent roles. I am not sure if a game with so many paths to the ending involving group dynamics has been mad before NV, so for a first try, I think it was great.
One thing I found odd was my completion time: Just around 80 hours including a long play through of Dead Money. I also didn't like that after the ending, I had to re-load a previous save to continue to the DLCs. I was a little surprised, as FO3 took me well into 160 hours. I will see how long the other 3 expansions take me.