My experience so far. Not good. 
I got the free version of Virus checker to try. Installed it and it did a scan. I was impressed as it found some viruses. shut down my computer. When I rebooted the license had expired. Key no longer valid, computer at risk! Within an hour, mind you.
Thought to myself, maybe that is the demo, so I bought a copy. (Good marketing ploy), Installed, and it did another scan. No problems found. I thought great! Shut down.
Rebooted about an hour later.
This version I paid for had expired as well! Key invalid, despite the fact that my account info shows both the Free version and paid for version with 364 days left and I copied and pasted the Keys directly from there.
I figure I should have enjoyed the free year, which lasted an hour, and definitely enjoyed my paid year, which lasted about as long. What do you think?