Call it personal bias, but from my first impression: STAY AWAY FROM M-AUDIO MONITORS
When I was in the market for some active monitors I ended up ABing M-Audio 5" monitors (forgive me, I don't remember the model number) with the Fostex PM0.4 monitors I ended up buying (the pair for $200).
Now the biggest difference between the two was volume, obviously, as the M-Audios were 5" woofers compare to the Fostex 4", but the difference in sound signature was even bigger. M-Audios were muddy all along the mid range, and lower mids were coloured to the point of being boomy and distorted. The highs on the M-audios were not very crisp, and again distorted with the lower mids that thumped in.
The Fostex' were impressive for being so small. The detail in the highs were impressive, not the best, but better than the M-Audios. The roll off seems MUCH higher. The bass however is pretty much non existant, but for me, that just means getting a subwoofer. I do plan on trading up to the PM0.5 active monitors after I get the pmSUBn subwoofer to match. Unless I end up finding a better set up for my budget.