Hey Kaspars, thank you for writing this.
I use WP MS with domain mapping for a small (18) blog network, where users can register in any site and comment in any other with single sign-on (I use “Remote login” in the domain mapping plugin). Users login at domain.com/login/sitename/, not at each site’s singledomain.com.
If I disable the plugin and start using your straightforward technique, would I lose the single sign-on part? I know WP MS is designed closer to WP.com with many unrelated blogs, instead a tightly-knit blog network.
I’d like to know if someone experienced this before testing with a live site (and I know, I should have a staging environment, but every day that passes is a heavier task).