Who to trust more -- a power block of flawed but generally well-intentioned Western democracies or Russia + China?
I'll go with the Western democracies pretty much every time.
Compare the allies of both sides in our local neighborhood. Japan, Korea, Taiwan, etc. are all democracies. Flawed though they may be, they're relatively liberal and free. Who are China's and Russia's pals? North Korea ... Burma (though fortunately this seems to be changing) ... Pakistan (increasingly) ... Do people generally want to live in China and Russia? Nope, they're struggling to get out. The same goes for their allies. How many South Koreans, for example, are risking their lives to escape to North Korea?
Also, the idea that the current Syrian dictatorship represents self-governance is ridiculous. That regime is trying to prevent real self-governance and China and Russia are trying to stop the free parts of the world from helping the Syrian people to get rid of their rotten government and have a shot at democracy.