There is a problem with Deferred Render (L&S = Lighting & Shadows) crashing some viewers. The Firestorm Viewer team thinks most people cannot run L&S. That may say more about who is using Firestorm and Phoenix rather than SL users. But, as far as I know there are no good stats to answer the question of how many people can run L&S, at least not in regard to SL users.
As we move forward this will be a more important issue. It certainly makes a difference in how Second Life™ appears on your screen.
What it is?
Deferred Rendering is a high fidelity render of lighting and in some systems shadows. There is no limit to the number of lights that can be rendered, which is a big step up from the 6 or 8 lights we could previously render in SL.
