When comparing Spring-boot vs Falcon, the Slant community recommends Spring-boot for most people. In the question“What are the best web frameworks to create a web REST API?” Spring-boot is ranked 3rd while Falcon is ranked 25th. The most important reason people chose Spring-boot is:
Boot is just a thin configuration layer over Spring Framework, as such it inherits all the strengths of Spring.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Inherits all of Spring's strengths
Boot is just a thin configuration layer over Spring Framework, as such it inherits all the strengths of Spring.

Pro Preconfigured starters

Pro Fast prototyping
Spring boot is built for fast prototyping.

Pro Kick down to Spring
Pro Built to build REST APIs
Falcon is designed entirely around building REST APIs. It achieves this helps a lot with it being lightweight and simple. It also helps developers take some design choices which would otherwise not be possible with a more general-purpose framework,
Pro Lightweight with minimal dependencies
Falcon is a very lightweight framework. This can be noticed simply by looking at the dependency list: other than the python standard library, six and mimeparse are the only dependencies.
Pro Performance is really awesome
Cons
Con Lacking in UI development
While actually very good and with a very complete and rich feature set to develop and maintain code on the server side, it still doesn't provide any rich framework for building good user interfaces.
Con Limited in scope
Being designed around building REST APIs and the fact that it's minimalistic with very few dependencies makes Falcon opinionated (you should build a REST API) and limited in scope (you shouldn't be using Falcon to build a news site, blog or ecommerce platform).
