When comparing Polymer vs Angular, the Slant community recommends Angular for most people. In the question“What are the best client-side JavaScript MV* frameworks?” Angular is ranked 9th while Polymer is ranked 13th. The most important reason people chose Angular is:
Angular uses the existing HTML structure and builds on top of it instead of requiring you to learn a new templating language. Because it's just vanilla HTML, it is more familiar, and easier for beginners to learn. Directives let Angular know which HTML elements are under its control, and how to use them. Being directly on the HTML it's more transparent what's going on, and it's possible to get a good idea of what the page is doing just by looking at the template. Also, it makes embedding possible, as you could have an angular app within an existing site so you don't have to rewrite everything at once.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Various basic components
It provides a base component.
Pro HTML markup is not string
HTML markup as it can be a non-string.
Pro Flex layout components
It provides Flex layout components.
Pro CSS is easy to apply
CSS can be applied far more comfortably than React.
Pro No need for special debugging tools
The presence od specialized debugging tools are advertised by competitors. The all features of web components are natively supported by browser embedded development tools.
Pro Excellent routing
The router is embedded into CLI for project creation and covers as web as Progressive web app, also fused with Polymer layouts out of the box. The shop template for CLI has a complete solution including the routing.
Pro Complete web app stack support
Full app stack from data tier to routing, progressive web app, responsive layouts makes no need to seek outside of Polymer ecosystem for application features.
In addition to waste set of mature web components in Polymer Elements along with Vaadin Elements there are thousands of web components in the wild comparable to jQuery plugins set.
Pro Excellent documentation
Polymer guides you as with tools (cli, build environment, app templates,..) as with complimentary documentation on all phases of app development from creation of app as progresive web app to production deployment instructions.
As Polymer is standards based, the whole community around those standards also helping in documentation and support.
Pro Based on web components
Web Components are a collection of specifications released by W3C as a way to reduce the complexity of web apps by creating reusable components. Browser support is currently poor for web components, however Polymer is developed to make web components compatible with modern browsers.
Pro API is easy to understand, based on standard
The Polymer APIs are split on application layers and follow standards on all possible ways: Web Components, CSS variables, async API via Promises and so on.
Pro Support for a composable component oriented architecture with directives
Angular uses the existing HTML structure and builds on top of it instead of requiring you to learn a new templating language. Because it's just vanilla HTML, it is more familiar, and easier for beginners to learn. Directives let Angular know which HTML elements are under its control, and how to use them.
Being directly on the HTML it's more transparent what's going on, and it's possible to get a good idea of what the page is doing just by looking at the template.
Also, it makes embedding possible, as you could have an angular app within an existing site so you don't have to rewrite everything at once.
Pro Provides dependency injection
With dependency injection, you can load in extra javascript and new functionality just when you need it.
This is particularly helpful with testing as you can swap out services for test services.
It also means in single page apps you can load dependencies only as you need them instead of loading them up all up at the start.
Pro Easy and straightforward data-binding
Data bindings are done on the DOM, which allows you to easily sync data between various parts of the DOM in a very succint matter.
<body ng-app>
<span>Insert your name:</span>
<input type="text" ng-model="user.name" />
<h3>Echo: {{user.name}}</h3>
</body>
This snippet shows how the model attribute "name" is easily bound across different parts of the DOM without having to set up any extra boilerplate.
Pro Huge ecosystem of third party components
Angular is an extremely popular JavaScript framework. Because of this, developers have developed a myriad of components which can be downloaded and integrated into any Angular application.
Pro Huge community that is quickly growing
Angular has the largest community out of all Javascript MV* frameworks and there are a lot of tutorials and guides out there for new and old users alike.
Pro All best practices
Cons
Con No server-side rendering
Polymer does not support server-side rendering. This results in higher loading times, more HTTP requests and it's not very SEO friendly, since search engines have no way of indexing a page if it's not rendered in the server.
Con Steep learning curve
Angular isn't a simple framework, and because much of the magic goes on behind the scenes, it isn't easy to go from simply using the framework to being able to actually change how it works and extend it.
Con It is almost mandatory to use Typescript
Although ES standard can be used, most of the documentation and resources are with Typescript.
Con HTML template does not comply to standards
Attributes are case-sensitive, which is against the HTML standards.
Con Difficult to use for isomorphic apps that render the initial template on the server in a performant way. Non issue for enterprise apps.
Con Explicit configuration
Users will usually need to specify stuff that is very obvious (template location, providers etc. ).
Con Two-way data binding is often considered an anti-pattern
Two-way data-binding means that a HTML element in the view and an Angular model are binded, and when one of them is changed so is the other. One-way data-binding for example does not change the model when the HTML element is changed.
This is a rather controversial subject and many developers consider two-way data binding an anti-pattern and something that is useless in complex applications because it's very easy to create complex situations by using it and being unable to debug them easily or understand what's happening by just looking at the code.