Recently I tried Billings 3, but decided not to upgrade.
Today I downloaded version 3.0.3 to see whether this version was finally worth it, and got a message saying that my trial had expired.
Although I could not run the program, I visited their forums and apparently this version is still buggy.
In addition, trying to run my previous version now gives me the following message:

"Your Billings database has been used with a newer version of Billings. Visit www.marketcircle.com to download the newest version."

The only positive aspect I've seen is that the upgrade price has been lowered from $35 to $25. I would rather give my money to a different developer.