Difference between Devstack & Microstack

Devstack & Microstack both provide deployment of Openstack on single node.

Is there any fundamental difference between them?

Devstack link: https://docs.openstack.org/devstack/latest/

Microstack link: https://ubuntu.com/openstack/install

Is there any advantage/disadvantage using one over other?

I know nothing about either project, but reading the pages you link to suggests they have fundamentally different implementation and use cases.

DevStack is built from bleeding-edge sources, and is intended exclusively for testing and contributing to the OpenStack technologies themselves:

• "DevStack is a series of extensible scripts ... based on the latest versions of everything from git master."
• "DevStack makes a lot of configuration changes to your system and should not be run in your main development environment."
• "DevStack ... makes many choices that are not appropriate for production systems."

MicroStack is a polished installable package, which can be used for prototyping systems built with OpenStack, and even deployed to production:

• "MicroStack is OpenStack in a snap which means that all services and supporting libraries are together in a single package that can be easily installed, upgraded or removed."
• "You can use [MicroStack] for development, prototyping and testing, but it is also perfectly suitable for the network edge, IoT and appliances."