I like MPL too (depending on context), but do be aware that (per section 10) Mozilla is allowed to ship new versions of the license and people can choose to use

I like MPL too (depending on context), but do be aware that (per section 10) Mozilla is allowed to ship new versions of the license and people can choose to use those new versions in place of the version you licensed under. This is not inherently bad — many projects are licensed under "GPL 3 or later", for example — but it's something to be aware of. See also CDDL, which is mostly MPL but Sun (and now Oracle) in place of Mozilla Foundation.