First, big thank you for D3, it's an amazing piece of work.
That said, DOM/SVG performance is still a problem with mobile browsers. We tried to do D3 based visualization tool that would work well in mobile. Especially with panning and zooming, which are natural gestures in mobile and often useful because of the limited screen estate, you will hit rendering performance problems easily.
With a proper use of CSS transforms, culling of data points and intelligent redrawing, you can get the performance to adequate levels on iOS Safari, but you have to throw away the pure data-driven documents approach and start to think it more from the "rendering pipeline" angle.
That said, DOM/SVG performance is still a problem with mobile browsers. We tried to do D3 based visualization tool that would work well in mobile. Especially with panning and zooming, which are natural gestures in mobile and often useful because of the limited screen estate, you will hit rendering performance problems easily.
With a proper use of CSS transforms, culling of data points and intelligent redrawing, you can get the performance to adequate levels on iOS Safari, but you have to throw away the pure data-driven documents approach and start to think it more from the "rendering pipeline" angle.