I have owned a Sadowsky modern, and they are absolutely wonderful. But, imo, I find less them versatile than some of the other models.
As mentioned, they use the soapbar pickups, which tends to be, well, "modern" sounding. But, imo, the unique character of the modern comes from the placement. The bass doesn't really have a neck pickup. It is more of bridge and mid pickup. This creates a very tight, mid present tone that you can't completely escape on that bass. Not saying it's a one-trick pony, but its character is inescapable. I absolutely loved the one I had, but I never once did a whole gig with it. I always used another bass when seeking a more "classic" sound.
The JJ Sadowsky basses can somewhat grasp that same tone by panning to the bridge PU as far as you prefer. It isn't as complex and unique, but in a live mix, it's very usable.
With either model, the beauty is that the Sadowsky preamp stays very musical even with a significant boost in bass. So, you can keep the low end very present when dialing up the middy, high texture tone.