I have often noticed some tearing if I don't overclock. That being said: I have never run extensive benchmarks or anything. The only reason why I started looking at the cli version of mplayer is because my gf is spanish and she wanted subtitles. That didn't work with the "additional subtitle support" or whatever it is called in the repo's. Tried all the other options (logically as I didn't want to force gf to work without a GUI), vlc, sib KMPlayer, etc. None worked. So I ended up teaching her how to type a command in the terminal and do it like that. Apart from that, she also learnt how to use mplayer on her netbook, and use the hdmi output, which I don't think is possible with the stock player. So, for us, cli mplayer was the best choice. It might not be for you, though.

However, if you type mplayer --help, you'll notice there are some options like framedropping and post processing, which may or may not help you.

Conclusion: Your mileage may vary.