I haven't tried two distinct screens, so I can't directly compare
them. I find the moving of the mouse from one screen to the other to
be intuitive and natural for me, but in reality, I rarely use the
mouse anymore. I probably don't need to use xinerama except that it
easily flows with my usage of wmii. For example, in wmii to move a
window into a column on the right of your "screen" you use
Alt-shift-l. I have my wmii set up to split the column at 50%. Since
my screens are the same size, that puts the split right at the edge of
the monitors. I always have more than one window open so I get two
screens each with a full screen window in it. It just naturally works
well for me.