It's not wonderful for the Russians; in fact, it's very stupid of them to do this.
China still thinks Russia stole its land so many years ago and they have a million Chinese prepositioned in Siberia in case something happens.
The U.S. is may be worried about this development, but if the Russian's realized what they are doing they would be worried more.
Chinese navy is not a danger to Russia. If Chinese were ever to invade Russia they would use VERY long land border instead of sailing around Korea to make a desant on Kamchatka. Russians need money and selling weapons is the a good business.
America should open trade relations with Russia and end the Brezhniev era sanctions. America could be better trading partner than China or Iran. Russia should be allowed to develop market economy.