Logs the contacts too, which is a nice feature. There are free extensions for this which I've used but for the money you should just buy this and be done with it. Pages of 5* reviews say it all really.
Well done to Tienda, as far as I'm concerned they've filled a gaping hole in the market here.
The backend reminds me of Magento in lots of ways, as does Dioscouri's whole business model. The extension is excellent. Perfect for a medium sized shop when you need to get things up and running quite quickly and inexpensively.
Why only 4 stars? Well I'd like to see more payment gateways supported, and also alternative shipping modules. There were some bugs (ie rounding errors etc), and some functionality which should really have been there but wasn't (ie you can display product prices inclusive of VAT in the shop but not in the cart - that requires custom work).
It is still in development though and the issues are being actively worked on. As far as I'm concerned it's ready to be used commercially and I hope the team that wrote it do very well out of it - they deserve to.