Interms of the make menuconfig layout and the actual make and make install process... its much more streamlined
all drivers and filesystem are categorized
as for perfomance..
the 2.6 series has a pre-epmtive feature that makes running linux lighting fast even on older hardware.
it is also designed to be stripped down to just the basics
modules are compresses so its footprint si small
memory mamangement is WAAAAAAAAAAAAY better than the 2.4.x series
even SMP is improved
its just better designed overall
I can't quote stats
but the experience I have with running 2.4.30 and 2.6.11-rc on a SuSE 9.0 install on a 1GHz processor with 256Megs of ram is shocking.
Then their is udev
it make usb plug and play almost where it should be.
i don't have to manually mount my usb drives anymore... with udev and hotplug its actually plug and play
and the best feature for me
HIBERNATION and ACPI
I can actually hibernate my computer and resume (something windows users take from granted) with ease... I do not powerdown my computer anymore unless I experimenting with the kernel and its been up for a while
so what I do is when my power from JPS goes and the ups is low... is to set the ups daemon to hibernate the machine
when i come home i just press power button and within 15 seconds its back on !!
the hibernate uses swap partitions
cd bruning is better.... i do not have to use ide-scsi anymore
dvd playback is better as well as sound because the latency of the kernel is remarkably lower than the odler 2.4.x series
even network is snappier with my NFS links back and forth to my compters.