Really great pair of monitors
Don't let the shape fool you, these are real monitors. I've had mine for almost a year now and think I have a pretty good handle on them. The large woofer gives these guys an impressive amount of clean bass . . . in fact, I prefer the bass response of these guys to the BM5a's (which I also considered). I do use the filter to cut back the bass, though, as it can almost be overwhelming. Cut back the bass 2 db's and it is perfect. The midrange and the high's are really solid and clear. Everything is pretty upfront, which, in my opinion is useful for mixing in the modern environment. I chose the DBM50's over the Adam A7x because I liked the immediacy of the Dynaudio's over the sometimes artificial sounding depth I got from the Adams. They are both impressive, don't get me wrong, but I prefer the no-nonsense presentation of the DBM50.
I mix at slightly lower levels than most, I think, so for me, these guys have PLENTY of power (I feed the monitors directly from my Apollo Quad). I've never had to turn them up so loud that I noticed any distortion. For most control rooms on the smaller side, I think these guys will hold up fine. Personally, i think of the Dynaudio Bm-15's as more of midfield monitors, anyway (I have used and love those monitors, too), so for nearfield applications, I think most will find the power of the DBM50's more than sufficient.
At this price point, it doesn't really get better . . . just different (as I mentioned with the Adam's). The DBM50 is less hyped in the lows and highs (especially with the bass rolled off) than the Events and Mackie's that I auditioned. They don't have as much depth as the Adams, but I actually found that to be an asset (they still have plenty of depth to hear reverb sends, delay, etc) as the mixes translate more easily to other systems. You definitely don't need a sub with these guys, either, unless you want one just to make sure nothing crazy is going on down there in the low frequencies. I still do half of my mixes at another studio that has both the Adam Ax7's and the Dynaudio BM15's as well as a dynaudio sub. While that is still my preferred place to mix, I've been getting much, much closer to matching my mixes at that larger studio since I got the DBM50's. If you have a home studio and you want to be able to track and mix at a more professional level, then I highly recommend the DBM50's. I got the DBM50's after having the KRK Rockit 6's for a while. With the KRK's, there was no point to really trying to mix before I brought it to the bigger studio because once the track was played back on the BM15's, I realized right away that I needed to start from scratch. The the DBM50's, my mixes usually only need a few small tweaks before they are ready. And even when the budget does not allow me to go to a bigger studio for mixing, I'm still able to get some great sounding masters from my home studio.