The AC LM models sound pretty close (to my ear) to a mid to late 70's passive Fender J Bass. The Sadowsky ash/maples, even with single coils, sound MUCH brighter, aggressive and 'active'. Very different IMO.
The AC models are among the most 'Fendery' sounding of boutique J's. The Sadowsky models are among the least 'Fendery' to my ear.
My AC LG is also much darker, warmer and more subtle sounding than the alder/RW Sadowsky I had... so the differences carry over to both models (alder/RW 60's and ash/maple 70's).
That being said, that ash/maple 70's type J tone is still quite upper mid present and aggressive, but the AC does it in a much more grindy, organic way like the older Fenders, versus the 'zing and sizzle' of the Sadowsky model.
Using the VTC type control on both the ash/maple Sadowsky and Alleva, I feel I can get them to sound pretty darn close to the alder/RW models (although, again, not to each other... the AC's sound totally different from the Sadowsky basses). However, I don't have any luck going the other way. You can soften that aggressive upper mid and treble response of an ash/maple J with a VTC pretty nicely, but there's no way to dial it in (IME) to a more 60's spec'd instrument.
IMO and IME!
Edit: I have that clip up of the LG and LM through a relatively transparent amp posted earlier in this thread, so you can hear the general tone and difference between the two pretty well (although they both had relatively new SS roundwounds, so they are both quite bright. I have nickels on my LG now, and it purrs!).