API lifecycle management mechanism of IBM often refers two gateways in their context, however, there differences are not discussed.

Micro Gateway refers a simpler local solution for developers  while the DataPower Gateway is for production use.

Capabilities of Micro Gateway are limited to invoke, javascript and validation policies only. If you want to test the functionality of API Connect, the easiest way is to use micro gateway with apic loopback application in your desktop not on cloud.

In contrast, the Datapower Gateway is a fully fledged solution with proxying , gateway scripting, various json xml conversions and much more. Moreover, this has two versions – virtual and actual hardware based solution.