The best I've managed is 2% skipped frames with one version of DVPlayer and 5% with another on my Sam440ep-Flex @ 733mhz.
It's watchable but not not ideal.
If you have a 2% frame drop at 50Hz this is slightly better than cinema (which is 24 fps). I have not measured my framedrops, but DVDs look fluid, even if I open OWB and some applications at 1280x1024x32 with compositing on. It seems however that DV-Player is taking about 70% CPU load on my Flex @ 800mhz.
And what is more: When DVPlayer is dropping frames it just continues without slowing down the system or becoming unresponsive. So I don´t see why some people gerealize this to: "You can´t watch DVDs on SAM." I can.