Another happy Bepu user here. My game definitely tests the limits of the engine, and it always performs like a champ.
Here's a somewhat outdated gameplay trailer with a lot of me talking very boringly. The link should skip you to the fun physics-y part.
http://youtu.be/7h_hObwKjNw?t=2m26s
Since then I've added more stuff to take advantage of Bepu, like
levitation and sliding voxel pieces.
For the curious: the dynamic voxels are MorphableEntities, and the static "world" voxels are StaticMeshes. Since the whole mesh has to be destroyed and rebuilt every time the world is modified, I split the world into chunks hashed by material type and location. This allows for faster updates and allows the broad phase to filter out a lot of collision candidates. (At least I think so. All I know is performance went up after I implemented it.

)
I've been working on this game forever. No idea if and when it will be released, but I will certainly reserve a redeem code for Norbo!