Warid LTE is the worst for following reasons...
1- Worst handset compatibility.
Although it runs on FDD 1800MHz Band 3, any handset that is not "Officially" launched in Pakistan is not supported by it. I have checked LG G2, G Pro, Nexus D821, LG G3 S (mini) and note 4 (N910C), all supporting the mentioned LTE specs but are not supported by Warid.
2 - Inconsistent speed
Zong is the winner here. consistent speed. Warid has inconsistent speed may be coz it is running on 5MHz band same as the voice while Zong is on 20MHz.