Concensus is Radeons have 10 bit and better video image. It also supports IDCT and Motion Compensation HW acceleration where as the Geforce is MC only with 8 bit video. Smoothness wise they're equivalent. The ATI comes with ATI player (Cinemaster codecs which by most reviews have the best picture quality amongst the software player--except may be the brand new PowerDVD XP 4.0) and Geforce with older version of PowerDVD (2.5 probably), depending on brand.
Radeon LE are pretty stable on most OS. It's the VE that is a little quirky due to dual head driver issues. Game horsepower wise, once you add the T&L tweak to the LE, it's close to the Geforce MX. Of course it's no match for the Pro, GTS, Ultra, or Geforce3 cards. Geforce 2 MX should be slightly faster on games.
Thus it's depends on you priorities. For video quality, Radeon LE will win over Geforce 2 MX. For 3D games, Geforce2 MX should win. For stability and ease-of-use Geforce2 MX should win also.