A while back I had the VR-4 GenIII (basic version, not HSE). I sold them as I had them in an apartment, which was kind of ridiculous, and switched to smaller speakers. When I recently moved into a house I kind of regretted that decision and got a pair of VR-33s. So I have owned both, though never compared them side by side or even in the same room, but I can give my impressions from memory.
What I remember about the VR-4 GenIII was a beautiful liquid midrange and very deep bass (which could be a bit overwhelming in a small room). In contrast the VR-33 is more transparent in the mid-treble but doesn’t quite have that liquidity in the midrange that I recall from the VR-4. The bass of the VR-33 is tighter and more articulated but less deep. The VR-33 are a better fit for a medium to small room both physically and sonically.
Would I spend the money to upgrade from the VR4-genIII to the VR-33? To be honest, probably not, especially if you’re happy with what you have. At least not without a careful audition, which you might find difficult with the VR-33. If you’re in northern California you’re welcome to listen to mine. I hope this helps.
Malcolm