Ever since the Boots of Mobility nerf, I have come to find that they have actually costed me my life; with the base of 25 movement speed, i can help but find myself stranded after the usage of both of my shadow teleports. That is when i began looking into alternatives: while the boots of swiftness may be faster than my current build, the do not provide the maximum potential of damage output on Zed's Shadow; this frustrated me. That is when during a normal match, I tried the Ionian boots that were supposedly for mainly supports. Before I knew it, the boots had given me basically a starting amount of 20% cdr, then the brutalizer gave me 30%. Before I even break level ten, I can have 40% cdr with a 72 second on my ult if the jungle is nice enough to give an energy champion the blue buff. All of this is accomplished while remaining over 410 movement speed and keeping the same old Zed build: the Bork, Last Whisper, Black Cleaver, GA, and the BloodThirster. Its all still there, only you have max cdr (Blue buff included) with a 48 second cd on your ult late game.
"With maximum CDR (40%) you can get off 3 Shadow Slash and barely get off 2 Razor Shuriken during a single Living Shadow or Death Mark."- http://leagueoflegends.wikia.com/wiki/Zed/Strategy