Sidi Mega are not really wide as in EE or EEE. They are wider than the non-Mega version but are far from comfortable for those of us with truly wide feet and/or high arches.
They will last a long time. Mine lasted 12 years of hard use until the soles literally detached from the last. But they never were truly comfortable for my wide feet.
I gave up on replacing the rubber sole pads after they wore out a few times.
Speedplay are probably the least walkable.
-Tim-