Horrible. Just doesn't work. Waited 45 minutes for it to crack "cyancoding" (with only lower case letters) and never cracked.
@generalpoxter: Hello! The reasoning behind this is that the password "cyancoding" is 10 characters. Even though you were only looking for lowercase letters, a 10 digit password is still very hard to crack. I don't completely agree with this website's algorithm, but if you enter passwords into it, it should give you a grasp of how much harder it is to guess when you add just one more letter (http://random-ize.com/how-long-to-hack-pass/\).