I also use Turbo ftp it is really good for verifying data for large ftp collections using the session mode. I normally use filezilla and check later with Turbo ftp to verify. The downfall is TurboFTP can only have connection thread working, not two or more like other ftp clients.
Best FTP client i know so far is filezilla v2. I couldn't get on with v3 it has to many bugs, and still has like above posts.