General rate: Negative
Very, very annoying piece of software ... it kept crashing! Although it says "Uses multithreading to verify emails at a very fast rate", which sounds like it is fast, this process of theirs is EXTREMELY CPU intensive (my 2GHz, 1GB of ram couldn't support it). Not recommended at all! I've now switched to an email verfier called eVerify from www.sprika.com - they say it handle's huge list, and they're right!