Should my users’ profile page URL be /user/bob or just /bob?

Currently, the URL to a user's page is this:

website.com/user/bob

But I'm considering changing this to be:

website.com/bob

Without the /user/ part. It comes across as much cleaner and easier to access, as user pages are one of the most frequently-visited pages on my site.

I have, however, a few questions:

1. Is this something I should do? Is it SEO friendly?
2. Would this be done within my code (my routes file) or would it be done through .htaccess or some other method?

Thanks.