So what's the downside? You almost never get optimizations like this for free. The post hints that this is also good for server workloads, but what suffers? Realtime would, but realtime usually involves a different scheduler anyway.
By the way, your post is the single most obvious statement I've read this year. You got upvoted just because you capitalized some words?
(TBH I have no idea why I got upvoted, it wasn't that insightful, but I stick by what I said)
(EDIT: I'm talking about gnome-startup. That's a stupid regression that never should've happened. The mplayer performance bug is totally understandable if you're mucking with the scheduler. What we really need is for someone (distros?) to pick up cgroups and provide a nice UI for it, some sane but nondestructive defaults, etc. Until then, this is a nice patch that keeps badly behaving programs from dragging down the entire system. At the very least, we mostly get user separation in multi-user environments.)
As long as the fixed overhead of the patch is small (which the linked thread seems to indicate) this should be a sizable win for desktop Linux boxes without much downside for server loads.