Given the recent changes to visa regulations in China in 2014, what are the official work visas in China?

Both the R and Z-visas are official work visas. For the time being, the Z-visa is the most common type used by foreigners working in China, and will likely remain so, considering the stricter requirements and remaining uncertainty regarding the R-visa. An employee on a Z-visa needs to subsequently apply for a residence permit. The residence permit allows the foreigner to stay in China for the length of time as stipulated by the permit, usually one year. It also allows him/her an unlimited number of trips into and out of the country. With an M-visa (or the previous F-visa) this is not possible, and leaving the country often means having to reapply for a new visa.