Yes, Google+ do help to get better SERPs. Not only Google+ but all social media shares, likes, tweets,etc do help to provide better pageranks and search engine result positions, provided we follow the following points:
The profile , which likes, posts, shares, tweets,the given content, should be genuine and have valid information on profile to be a valid profile built by a human.
Unsolicited likes,shares,tweets are not given any value by google.
The creator profile for the contents on social site should have good reputation also.
For Better Understanding Please Refer To The Following Matt Cutts' Video