SSH Telnet

What's the difference between normal telnet and SSH telnet?

Normal telnet traffic is unencrypted, which in the worst case can mean that someone could view everything you type including passwords.

SSH (strictly speaking SSH2 protocol) traffic is encrypted to prevent this.

There are ongoing updates to OpenSSH, the system most commonly used, to improve performance, fix general bugs, and most importantly fix security holes that may have been found in previous versions.