On zed I think that the rework is going to make me buy yomuus every game...20% cdr is nice and 200 extra hp is good too but the damage nerf really feels bad and the flat Apen is gone now...is this item even worth getting anymore mostly on zed, talon, and jayce
EDIT: In addition, I think Youmuu's Ghostblade has been superior for a long time already.
On Jayce however, it's depending on your playstyle. If you play him as an assassin to burst down their ADC or AP mid, Ghostblade it is. But if you fight with tanks or offtanks Cleaver is stronger.
Long story short: Ghostblade is superior on assassins and bursty champions that want to kill enemies in the blink of an eye, while the new Cleaver is better for bruisers, offtanks (or ADCs) to melt down the opposing tanks. Cleavers offers a nice amount of stats, but the HP and 20% are not as important on assassins as the active from Ghostblade.