Any experience with Zamtel ADSL internet ? (Lusaka)

Hi again, wondering whether anyone has experience with the Zamtel internet via phone line (ADSL) offer? On first view, unlimited download and ADSL starting at 100,000 per month seems like a no brainer compared to these rip-off Airtel and MTN dongles...but if the service is slow and intermittent. So if anyone has experience of this drop me a reply, thx Ben