I am using proftpd with Mandrake 9.1. It isn't hard at all to set up. I was like you, looking for an ftp server with a gui. It isn't really what you need though. I installed proftpd but didn't know how to use it. So I did a little
on the internet and I still couldn't figure it out. So one day I booted up my machine and watched all the kernel messages and found out proftpd was already started. So I just ftp'd from another computer to my proftpd computer using my linux user name and password and voila!! I was surfing my Linux box!!
So it isn't hard to use proftpd, all you have to do is set up users like you would normally, and use the username/pass as your login to proftpd server.