I've long maintained, and still do, that both products have legitimate places. Whether you consider Breakaway "current" or not, you'd be hard-pressed to find a hardware-based processor for under $6,000 that comes close to what it still does. One feature that still makes the software valid is its low latency in the ASIO version.
Stereo Tool has some nifty new features, and for many, it may be the current "new thing". It does all of its magic at a price though... in processor power and time.
You have to decide which model is best for you, as you would in a "Omnia VS Orban FS Vorsis" shootout.
In any case, Leif owes an explanation to no one. At least partially with the information he gleaned from us as beta testers, he manufactured another piece of his future. For that, he gave us a very advanced piece of software for pennies on the dollar. Beyond that, he could call the Breakaway software final and it would be just fine as it is... for what it is.
I know people who still think the old MBL 2 & MBL 4 processors have applications. Nobody's harassing that author for updates.