Kinda heavy to strap the thing onto your arm though, it's like 4 ounces without the battery or disc. The typical flash player will weigh about 2-2.5 ounces with the battery.

Also it's still got moving parts. Flash memory is solid state y0!

If you're buying the thing mainly as a workout toy I'd go with flash. If you want to use it for a buncha things and you'll work out with it every once in a while, the netMD ain't a bad choice.