The bunny-test works very well on my ipad mini (first generation).
I can add 2000 bunnies at 60 FPS
It's very weird because all the others test I did on IOS8 was very very very slow (maybe 1-2 FPS) , and some of them are not working at all (on ipad mini)
I think it depends of the number of pass used in each demo. In the bunny demo, every bunny is a sub-mesh of one single big mesh, and every bunny share the same small texture (this size of the texture & buffers is probably important).