Calling on Malzahar Players
So, I like to think at this point in my League gameplay I'm a mid lane main. The mages are hands down my favorite type of champions. So, I was saving up 4800 IP for the purchase of Ziggs, but Malzahar is free. So I decided I would give him a shot because after some reading its apparent that Malzahar can counter a number of popular mid lane champions. So obviously Ziggs is more of a siege champion, whose big on zoning enemies that can't trade in lane with him. Malzahar seems like the typical mage, having great range as well and some sweet burst. How would you guys compare the two?
I do intend to play Malzahar for the rest of the week and that brings me to the build. I was following a build that used Warlords Bloodlust, featured Rod of Ages & Rabadon's Death Cap as it's core. My idea was to build him somewhat different and wanted some opinions on what this build seems like. I was going for a more DoT focused build. It would be Deathfires Touch, Morellos & Liandry's core later building Rylais. I understand this build will indeed take away some of the burst at the cost of more DoT and the slow from the Rylais. What do you guys think?

since his voidlings can proc the slow passive.