Don't mind if I step in, and comment too.
They have this description on their website:
Exterminate It! antimalware extremely effective against active malware / rootkit infection. We are trying to help every customer. If we cannot help - we provide immediate refund. Check our reputation on the following websites: Verisign Trusted Seal, SiteAdvisor, Norton SafeWeb, HpHosts.
1st Question for them: Why do you have to *try* to help every customer? What happen to just helping them? There is no try. Either help, or don't help.
2nd Question: If they thought of customers correctly, they would not need to give refunds. So why offer refunds?
3rd Question: Why do they say check their reputation, when they know they have a bad reputation to begin with?
Malwarebytes Researcher, MysteryFCM, posted a topic about Exterminate-It, and an employee commented on the thread: http://forums.malwarebytes.org/index.php?s=&showtopic=5928&view=findpost&p=25719
In his/her comment, they said: "I registered here just to make you sure that we are not producing rogue antispyware product."
Who needs to "make sure they are not producing rogue software"? Why even question yourself for your company?
Prevx thinks ExterminateIt.exe is infected: http://www.prevx.com/filenames/1284738397264589682-X1/EXTERMINATEIT.EXE.html - which is based on heuristics/behavior most of the time.
Overall, their reputation is somewhat frightening. So, choose as you please.