Like MadameFLY, above, I also use Mixmeister, and I echo her reply above, although she's got a few years use on the product beyond mine. I've been using the MM line since around 2002, as I recall, having started out with Mixmeister 3. Moved from version three to MMPro 5 and then MMPro 6, then on to the Fusion release.

I'm a big fan of the product, but unfortunately, in the last couple of years, product development has severely slipped to the point where I would no longer recommend any current version of the line. Mixmeister, as an independent company, was bought out by Numark in Spring, 2007 and the MM Line began a subsequent painful decline in application reliability and robustness about 18 months after, much to the dismay of all of us in the user base, and particularly to those of us who have cherished the software over the years.

The last stable releases of the product that I care to recommend came out in Spring and Summer of 2008. Respectively those are:

Mixmeister Studio 7.2.2 for PC (suitable for studio mix production and limited remix production)
Mixmeister Fusion 7.3.2 for PC (suitable for the above, plus live performance and was released concomitantly with the Mixmeister Control Board for additional flexibility in live performance)

I have utilized versions of MMPro through Fusion in live performance for nearly 7 years. I have been particularly happy with Fusion 7.3.2 that I currently use in live performance, paid gigs here in Chicago with the Mixmeister Control Board that I have (which is a prototype--dated April 2008--to the mass-production release model--came out in fall 2008).

According to statements released by Numark, they are currently engaged in a reworking of the software code to deal with issues that have arisen in the development of the code over the past several years. So, I remain hopeful that the result of this work will be a fully functional, updated release that fixes all known major issues.

Meanwhile, I am quite happy with Fusion 7.3.2, and no matter what happens to the product down the road, I am comfortable with utilizing my kit as is for the forseeable future.

If need be, I would probably follow Dr. sY's recommendation, which I have also received from others, which would be to move to M-Audio's Ableton Live product line.

If you are serious about purchasing/utilizing the MM Studio or Fusion lines, I would contact Numark directly and request direct access to one of the above mentioned releases.