Both are necessary feature of social experience of site. +1 indicate the popularity of post while share help post to increase it's visibility to more and more people.
In my experience, I think that both shares and +1s are best in Google+ because it helps you get noticed and be one of the thought leaders in social media...
Both are having same value, it just depend on how you want to use Google+, if you want that your post must be visible to most of the peoples then share is the good one, and if you want that it must be popular then +1 is there.
I think both are having equal value, it just depends on your needs, if you want to increase the visibility of your post then share is better, while like is best if you want to make it popular.
I think sharing is better than +1 because if our post will be visible to more and more people then there is a great chance of getting more +1 if our content is good, but if we will get more +1 then there is not that much chance if it will not be visible to others.
Both are having an equal importance as the role of both the things are totally different, +1 helps you increase popularity of your post, while Google share will increase its visibility.
Anything is better for your business website, whether it is share or +1 as you can see both, but there is one advantage of +1 is it will show in Google search as how many people have +1d your business.
Both are better friends! Because both are having different nature, +1 increases the popularity while share increases the visibility. But if I have to choose between the one then I will choose +1 because a popular post always brings visitors to it.
I think share is better than +1, because it will increase the visibility of your post, and if your post will have that much quality that it should be liked than you will automatically get +1, and it will be the organic which will help you a lot.
Both are important for post. +1 button is for how your post popular is whereas Shares shows how many peoples are coming through your circle of circles.