My work runs on Basecamp. We chose it for two reasons, first because it did (nearly) everything we needed it to do, second, because it was being developed by a company we loved.
Now, it's completely integrated into our days to day production. We depend on it. If I walked in to work today and Basecamp was down, I might as well turn around and head home. We've let 37Signals premiere product become essential to us.
As of today, we're using their formerly premiere product. And if we wanted to upgrade to their premiere product, we'd lose completely essential feature.
Yes, they can say that Basecamp Classic will be the same great product it's always been, but it won't. Part of that greatness was innovation, and I don't think anyone believes that 37Signals will continue to innovate with a product that has "Classic" in its name.
The solution isn't hard. 37Signals just needs to be clear.
Will critical features like Time Tracking be in a future version of Basecamp, or will that requirement make us, forever, second class users? Because, I'd rather be a 1st class user at one of Basecamp's competitors than a 2nd class user at the service I've been using for the past 4 years.