There are some advantages to a Century 680V or W, or a 681. The problem is that those airplanes have been so cheap for so long that they've almost all been neglected, and by the time you've spent the money to make them reliable, you could have had a 690.
And a 690 is a better, faster, more reliable, more maintainable airplane. You can get parts for a 690. You can find people who know how to work on one, and actually have worked on one in the recent past.