Review on Suhosin by Matt Larsen

I like that it's free, has good support (both of which are essential when you're using a web host), and offers some pretty robust security features. The only downside about this product is that it doesn't seem to be well-known by other hosting providers - though there may just not have been much need to use it yet. We've used it with our sites on several different hosts, but never had any issues or complaints until we moved them all over to a new server at Rackspace. Previously they'd always worked fine, so something changed between us moving them off one host and onto another. Our problem was solved once we switched back to Suhosin.