Leaving aside the rather bizarre reasoning for the thread (to marry or not, for the sake of a piece of paper!), and the political OMNI material, the valid question is what are the rights, benefits and obligations of permanent residency?
A few I know about:
1. Permanent residents are treated as Chinese citizens for taxation purposes: in common with US, but almost no other country, Chinese citizens/ PRs are taxed on world-wide income, i.e. OP's non-China income would become subject to Chinese taxation (double taxation treaties etc notwithstanding).
2. Non-Chinese citizens/ PRs _cannot_ benefit from state retirement benefits: e.g. I pay substantial amounts every month into a retirement plan that I can not draw on, when I retire -- it's basically an interest-free loan to the Chinese government, which will be repaid when/ if I leave the country. My understanding is that PRs _can_ get retirement benefits.
3. There are other niche benefits that are just for Chinese citizens: e.g. in academia, right to purchase highly subsidised housing. PRs can also avail themselves of this benefit (GinFizz: is that correct?).
4. For those on standard residence permits (e.g. myself): once we cease to be economically/ socially useful, our visas are no longer renewed...by definition, PR does not have this rider...this is the main perceived benefit for several of my friends who want to settle in China, and are getting "longer in the tooth".
5. As stated above, getting a PR permit is extremely painful, especially if one has resided in more than one country over one's lifetime...
tb