I know what you mean about the ups and downs. Overall Effexor has helped me (after trying 4 others), but still having yucky mood swings, so I am now on Tegretol as well. This has been wonderful for me - my mood swings have pretty much disappeared and I don't know how to describe it but say that I feel like I have turned a corner in my depression.
I recently went through a personal trauma and not so long ago, I would have been an absolute misery with depression. This time, I am so pleased to say, I was sad, and I cried, but I knew the difference - I knew I would be ok.
It was such a wonderful realisation! I have just started weaning off the Effexor very slowly (I don't care if it takes me 12 months lol), baby steps, I'm dropping 37.5mg a time and so far it's been 2 weeks. My psychiatrist would like to see me drop 75mg in 6 weeks, but that's not going to happen lol - slow and steady when I'm sure, with fortnightly visits to my GP.
Best wishes to you.