I can compare fglrx (used it for 2 years) and radeon (used for 2 months). And besides worse performance in 3D and smaller power consumption, fglrx is much worse and causes some problems with my laptop. Not to mention that when I used fglrx I was afraid to upgrade the kernel because it forces me to recompile fglrx module (with all the strange DKMS thingy which is very strange to me - I just want to "make install")

Open drivers are good for debugging and avoiding crashes, and for flexibility, re: Linux kernel versions and API changes over the lifetime of the device.

Actually you are right. The problem (from user point of view) is not licensing. The real issue is the drivers being out of tree, making them much more fragile. I'd like to be able to update kernel and/or xorg without having to worry if binary blobs explode on my face.