Filezilla

Filezilla is the standard for FTP access across multiple operating system. Use Filezilla when you have to work on both Linux and Windows or plan to migrate from one to another some time in the future.

Download Filezilla from filezilla-project.org.

Any operating system

You can use Filezilla on Linux, Windows, anywhere. Filezilla works the same on every operating system. The only weird thing you will strike is a common FTP handling of text files where end of line indicator characters are changed. You can stop that by setting transfers to binary. Everything else works without change.

Multiple access

You can access multiple sites or multiple locations in one site using tabs. When you select a new connection, you are asked if you want to reuse an existing connection or open a new connection in a new tab. A new connection can be a different site or an existing site. If you want to copy to three locations on on site in parallel, you can open three tabs to the one site and change each tab to a different directory.

Conclusion

Filezilla is one of those must have applications unless you are in the freakish situation where you only every use one operating system and will never change. Never changing is probable if you are at the end stage of a terminal illness. For everyone else, Filezilla is the FTP client of choice.