Shenzhen Airlines officially joined Star Alliance on November 29, 2012, at a ceremony that took place at its main base in Shenzhen Airport (SZX). The airlines parent, Air China, was sponsoring the airline’s joining to the alliance.
Shenzhen Airlines operates a narrow body fleet of more than 100 airplanes and serves domestic and regional airports. According to the press releases, they are planning to order some wide body airplanes and that would imply long-haul flights sometime in the future. The airline was founded in 1992 and started operations in 1993.
You can already earn and burn on Shenzhen airlines. The earnings rate for United (check your Star Alliance airline’s page for your earning info these are not uniform) frequent fliers are rather low on discounted economy and you don’t earn Premier bonuses on Shenzhen as you do with some other Star Alliance airlines.
The award inventory is not available on United.com yet. It is, however, available already on Air Canada’s Aeroplan. So, it should be soon on United and other Star Alliance carriers websites that allow online award bookings too.
It is really difficult to tell any differences between Chinese airlines. I have flown China Eastern and China Southern (both are SkyTeam members), and Air China (Star Alliance member and the parent of Shenzhen). I have yet to fly Shenzhen but for sure will at some point.