about:flags is useful for testing but, in general, you shouldn't switch on random features. If you're doing web page development and want to see how hardware accel affects things, then sure. But if the feature was ready for general use, it would be enabled by default. It's not worth crashing your browser for a few extra frames per second.
(And pre-rendering is something completely different, not related to hardware accel at all!)
Prerendering is an experimental feature being added to Chrome to potentially improve user-visible page load times. Prerendering is triggered by <link rel=prefetch> elements in referring pages. An invisible RenderView is created for the prerendered page, which will do full loading of all dependent resources, as well as execution of Javascript. If the user navigates to the page, the invisible RenderView will become visible.
I've had a bunch of things in about:flags on for the last few versions (pretty much as soon as I found out about it, which I think was in 7.x), including both of the hardware acceleration options. It hasn't led to any crashes, as far as I can tell, by which I mean chrome hasn't crashed since at least two versions back. YMMV, but it seems to be a fairly safe thing to do.
Can I ask, is any of this going to speed up SVG rendering as well? I noticed that it mentioned "GPU Accelerated 2D Canvas". I'm working on a web app that utilizes the Raphael JS library and SVG heavily, choosing that over Canvas. So, should I have chosen differently? Is Canvas going to get a lot faster vs SVG? Or will these speedups aid both?
I believe that speeding up SVG using the GPU is planned but that a few intensive operations on canvas are likely to get switched on first (image compositing, for example).
I had hardware acceleration switched on, but I turned it off. I run Linux on a laptop and, from what I've read, xorg's EXA and 2D/3D through OpenGL is problematic for things like minimum power and P states. Heat is already a problem and I don't want the laptop using the GPU unnecessarily.
YMMV, but I've had problems with Google Maps -- specifically zooming with the mouse scroll wheel -- when I had Chrome 9's hardware acceleration enabled through about:flags.
about:flags is useful for testing but, in general, you shouldn't switch on random features. If you're doing web page development and want to see how hardware accel affects things, then sure. But if the feature was ready for general use, it would be enabled by default. It's not worth crashing your browser for a few extra frames per second.
(And pre-rendering is something completely different, not related to hardware accel at all!)