Nothing against Alesis from me, but their powered MKII monitors just didn't work for me. I bought a pair and auditioned them for a week in my very small studio. The low-end was so overwhelming that I couldn't work with them. Stuffing the bass ports with socks didn't help enough, and the absence of EQ switches gave me no options for adapting the sound to my room. I don't blame Alesis, though, because I know that my studio is quirky sonically and that I'm unable to change the room much (family considerations). I moved on to a monitor system (M-Audio BX5s + sub) that allowed me some EQ tweaking, and that did the trick.
By the way, I've noticed that the new line of budget Alesis' monitors has wisely added EQ switches. I've heard nothing about these new monitors, just seen the ads.
J.