Can only be recommended.
We have used them on a number of sites and servers.
There was 1 site who we had some problems with that kept getting their logins found. Even do we uses random pic+user+pass before request are send to password file from the members login page then these Russians kept finding a way to get in.
I am very happy to say that we no longer have logins stolen!
After 24 hours these guys send us a report with what they found and how to close the holes.
Great skills and good communication highly reccomended for anyone who is sick of seeing customer leaving due to their suspended login.
