Congrats on the Raspbian update. Before this update, I could not use the experimental 3D driver. It just flaked out with my monitor and gave me a blank screen. Now it works!
Even more interesting, I fired up the 3D modeler Blender. Without the 3D driver it was obviously unusable and some of the onscreen elements didn't even show up.
Today I've spent a few minutes playing with it with the 3D driver, and at least for simple things, it seems to work fine and doesn't even seem too much less responsive than my desktop system (quad core i7 with 16GB RAM)! And rendering simple scenes is even pretty quick.
Only problem so far is that keyframes don't seem to be working right. I add an object, position it, give it a position keyframe at time point 0, do the same at another location at time point 250, and it just repositions it as if the keyframes don't exist (it's even moved to the new location at timepoint 0). That is not the sort of problem I was expecting, so maybe something else is going on.
Oh well maybe it's a fluke. I'll keep playing.
Long term I wonder if Raspberry Pi's would be more efficient than desktop computers as a render farm. Sure I'd need more of them but given their cost and electricity use, they might be more economical.
But now you can chalk up something else you can teach kids on a $35 computer - simple 3D modeling!