Like or +1 Which should I promote

As the title suggest...which should I promote to visitors to my site - Facebook's Like - which would promote my sites to my visitor's Facebook friends.

Or Google's +1, which doesn't have the same reach, but could help in the SERPs down the road, could increase the chance that my visitors return to my sites and could promote my sites to their contacts via SERP results.

Please don't say promote them both...as I really don't want to water down the effects...so I am all in on one. Question is, which one?

Water down the effect? If someone likes one of my articles they're regularly tweet, like, +1, stumble, digg it, etc.

why don't you go for both? in wp, there are plugins that enable you to integrate 2 buttons

Both are google ranking signals(officially announced) but less weight than the backlinks

FB brings huge traffic to me too. Google +1, not so much. Google search traffic, yes, but +1 at this point? No.

like first.. then plus 1

Like and +1,is that so hard?