I've heard both. The DM5s are clearer and have a better stereo image, as you'd expect from a smaller cone. The ADM9s have more headroom and bass and sound bigger. Better suited to orchestral music.
I didn't think power output on the DM5s was an issue for anything otehr than large-scale orchestral music. Look around the technical journals and you'll see that using any passive crossover loses 3dB or more, so a 50w active can be equivalent to 100w passive.
It's a shame these things aren't specced properly but then who does nowadays? Since the Linn/Naim post-fact marketing in the 80s, reliable engineering reviews have all but disappeared.
I don't own either speakers, btw.