On a few different blogs I operate, the Facebook like button definitely results in more traffic. However, I believe the chance to engage in conversation on a particular subject is greater with the +1 button.
Facebook's Like feature has been around longer, of course, but I think Google +1 is definitely becoming popular now as well.
The facebook like is still much better for traffic on websites but the +1 button is growing quickly and will soon be a competition to the FB like. I prefer facebook like.
I'd vote for neither since people will tweet or write about your sites's content elsewhere when it is of good quality. However, between google plus or facebook like, I would still prefer the facebook one. It is far more reaching.
for now facebook is good..but after some time when google will fuly lauch G+ then i cant say anything..google is very creative...they will do some bang..wait and watch..
Because of the time spent on the web FB like enjoys more popularity but loyal Google users are seriously considering the +1 option.