I'm torn... without wanting to go into "best" vs "favourite" again >.>
I adore both songs, and think November Rain is actually the better written of the two, has far wider appeal and that awesome build up - it's an iconic song for many reasons and certainly evokes more emotion in me... BUT, at the moment I will not listen to it for certain reasons, and so if I was to vote on which song I would rather put in a playlist it would definitely be Estranged. That's not to say that Estranged is not a good song in it's own right, or even an excellent song... and yet despite these things and feeling that way about November Rain - I also don't want to vote against Estranged >.<
Which is my favourite? I actually can't decide.. majority of the prefential differences come down to mood and I actually don't think I can distinguish between which song I like more. If you threw Coma into this mix it would be even harder >.< I don't think I can separate the 3!