I don't understand the word proprietary, maybe you mean the drivers made by ati. I haven't tried those drivers after applying the patch, but tried them about a week ago, and there was some artifacts on my display which went away when moving mouse over them.
The drivers which originally came with XFree, work fine for me, even DRI.
Tested a few games for linux, Myth II, Rune and with winex3 I tried Warcraft 3, which also worked nice.
I tried the patch from DJ's page into an 2.5 kernel without success, got only kernel panics, sound missing completely, no network.
Oh, and my radeon is 8500QL (128MB). Anyway, thanks for hacking a hacked patch, it works great!