The price is definitely reasonable, the extension works well and the support is excellent.
Boy, I've had this installed on a few of my sites and the one with the most traffic certainly gets many attempts to hack the database. I think this is a pretty important plugin to have since there are just so many files that could be touched. And the owner has had very fast response time. I highly recommend it!
Security is becoming a huge issue and I manage about 100 Joomla sites so I test a lot of security extensions. This one works right out of the box, and it gives me a log of attempted exploits against the site, does a really good job.