strongbox offers better protection for your websites as it resides on your server and it checks a number of factors to decide if a userid/pass is being traded or if an IP is being used in a hacking attempt.

I have been recommending strongbox to my clients and all but one love it.

pennywize is a good choice as well, it was the leader in protection for years, but overall I would recommend going with Ray's strongbox product.

cheers,
Luke