After using Google plus (g+) for a while, I think I am still going to tweet (or whatever g+ equivalent) more in twitter. My reason is very simple; I need statistics of my activities. In twitter, I know the number of tweets I have made and so on. I know if I talk too much (the ratio of #tweets/#follower is much higher - a metric I invented ha ha ha).
There's no such feedback (karma of some sort) in google+. Even 4square has badges. I need that kind of feedback.