After some time I took the time to test ExpanDrive again. Unfortunately, the program is still not recommended. The connection to my FTP server is slow and unreliable (sometimes it works, other times not). Also the file transfers still work very unreliable. I tried to transfer a 2 GB file, every time I get an error message that the transfer failed. After a few more attempts, I gave up with great disappointment. To still charge $50 for something like this is an impertinence on the part of the developer.
I recommend using the competing product CloudMounter. This is not only cheaper, it also works reliably as you would expect.