I don't set up ssh by default, as most people wouldn't use it. That said, I'll give ssh access to anyone who wants it. For me, I would never use a webhost that didn't give me ssh access, so I wouldn't deny it to a customer. For example, when I'm debugging a php script it is much easier to vim the file on the server than it is to download, fix, and reupload.
I don't see ssh access as much of a security risk beyond the risks we all take by offering shared hosting. Anything that can be done in ssh can be done with a php or cgi script, and passwords can be brute forced just as easily through ftp or email as they can through ssh.