Google+1s do a lot help in boosting up the ranking of your website on SERP. Google itself said that +1 means that you the recommending the content on Google. They are also used to increase the Google page rank of the web page. But don't add +1s by fake accounts because Google is smarter enough to detect +1 by fake accounts or done through any social exchange website.
The only thing that counts towards PageRank (PR) is the count of in-bound links to a page, and the PR of the pages on which those links appear.
I am using g+ for my site, but its hardly paying any benefit to me as visitors attracted via g+ are very few or we can say near to negligible.
Yes I am very well satisfied with the features and services of Google Plus. If offer many essential social media benefits. I have always focused to build a well designed profile on Google and it helped me a lot to do brand promotion.