You just have to understand what you're getting.
It doesn't
provide ANY security to your website.
It will check your servers to for a wide variety of common exploits and let you know what changes need to be made to keep your server as secure as possible.
I didn't do extensive A/B testing to see if it actually improved sales, but I did trust their reports and case studies that showed that it increased sales for a wide variety of businesses.
I don't know if the seal needs to be "hackersafe" in particular. They are doing a great job of building a brand and selling merchants. Almost every website you go on these days has the seal.
But I do think that "some" type of 3rd party verified seal will help to build confidence in your buyers. ControlScan.com has one that's similar and I think there are a few others. HackerSafe just seems to be the biggest and most widely used.
Try to negotiate with them on pricing though
