If you find that SSH is slow to login it’s likely because due to DNS resolution.  When logging in via SSH the terminal will immediately prompt for the username / login (login as:) but after typing the username the terminal will hang for a short while before asking for the password.  This is because after the username has been sent the server will perform a DNS lookup and this is likely failing.  Check your /etc/resolv.conf and change your distro’s DNS resolver.

I’ve often seen this when a  machine has been configured in one location with a DHCP internal DNS resolver then moved to another network.

Hope this helps!
Jay Greig