I love Influenster, it was a slow start at the beginning earning badges and and finally getting my impact score to high but after a few months I was on the short lists for campaigns and have received one box so far. I think it's a great way to try new products when you are a good fit for the campaign and it's also a great way to become more engaged with your followers, become a true influencer and share your honest opinion on products.
I've seen lots of people complain that they have to do too much for the products... You are receiving free product(s) to reveiw if you are selected for the campaign, if you want a guarantee of products constantly, pay for them through a subscription service such as Ipsy.