MyBinding.com

We were looking for a partner that would allow us to implement advanced retention marketing techniques without spending a huge amount of money. We evaluated all of the major ESP's with integrated services and ended up selecting Windsor Circle along with Mailchimp. The extension takes all of our daily sales data and updates our subscriber lists and populates profiles based on their purchase history, lifetime value and runs RFM analysis to determine a contact's relative value.

We have used the extension to set up a welcome series, replenishment campaigns, best customer emails, anniversary campaigns, win back series and to send single sends to specific customer groups. We get a strategy manager along with the service that helps our in house email team learn and decide what to work on next. Plus we get reporting on lifetime value and retention revenue. For the price point and feature set you really can't go wrong with this product.  quoted from review on MagentoConnect.com