Not sure what you are trying to compare? ftp is for transferring files, etc.... and ssh is for logging into remote systems.
ftp = (not encrypted) file transfer to/from a remote system over a network
sftp = (encrypted) file transfer to/from a remote system over a network
telnet = (not encrypted) login to a remote system over a network
ssh = (encrypted) login to a remote system over a network
(not encrypted) is going to be faster... but..... everyone can see what you are doing by sniffing the wire.
(encrypted) is going to be slower but everyone will have a harder time sniffing the wire and seeing what you are doing.
If you DO NOT CARE about people seeing what you are going and it is completely OKAY for them to "freely steal" the logins, passwords, authentication credentials, etc that you are logging into a remote system with, etc - (not encrypted) can work for you. (ALSO) if you on a private network between 2x private hosts and you are really sure there is a wwwaaaaayyyyy less chance of someone trying to steal your credentials (not encrypted) (can maybe?) work as well.
If you are using a public network like the INTERNET or a WAN, etc you might want to use a (encrypted) network connection between 2 hosts.
(ALSO) with 2026 networks and hardware "slower" isn't really a concern anymore -- if you are using a dialup modem or a slow packet network it might still matter?
Where do you want to go today?