I have used quite a few different services of your kind, and I think yours provides the most value for the money of any I've seen. Great tool!
...having found your service by chance, we've been completely happy and pretty surprised actually. You offer a lot of features, with a very reasonable & logical rate system. ...How much your service will help is possibly beyond your understanding, but I'm sure you've heard that from other people using your service.
You have a great product...I LOVE the form generator for collecting emails to put on my site. And the testing process it totally cool. Thanks for such a well thought out product.