Some of my smartest customers agree to disagree. It's that close, and I go back and forth on this question myself.
I think the particular strengths of your system, and more importantly their weaknesses will ultimately tilt you in one direction or the other.
I'm hesitant to say more on this forum because I don't want to turn the dialog into a sales pitch (we can talk privately or on the Galibier forum where you'll interact with many of the same players).
Sandboxes (with a couple of tricks applied) get you so much of the vibration package, that I wouldn't think of anything else until I got my rig up to Stelvio Platter / Triplanar / Dynavector XV-1s status (along with dialing in at a minimum, my phono stage).
I'm waiting on delivery from TimberNation, of two sandboxes I'll be taking too the Audiofest next month. Those of you in attendance will be able to see his work which is priced quite reasonably.
At such point that I receive delivery, I'll feel much more comfortable about making a recommendation, but I'm at present, guardedly optimistic that this will be an ideal solution for most everyone.
In addition to "solving" the vibration problem, it will address the problem that many have in transitioning to a turntable with a larger footprint. It will overhang a traditional rack, and employ spikes (resting on the existing top shelf) to facilitate leveling where it might not currently exist.
Thom @ Galibier