Efficiency: projects that used to take months and hundreds of lines of code now can be achieved much faster with well-structured prebuilt patterns and functions ready to build upon.
Costs: most frameworks are open source and free. Since they help programmers to build custom solutions faster, the ultimate price for web app will be lower and save you a lot of time.
Angular.js is often referred to as an Model-View framework and among the top benefits, for startups and mid-sized companies, people name: quick code production, easy testing of any app part and two-way data binding (changes in the backend are immediately reflected on the UI and so on). Since release its ecosystem has gone beyond imagination. As for now, it is reasonably called the most used JS framework for SPAs (Single-Page Applications) development and it boasts the largest community of developers. As you know we wrote a lot tutorials about Angular JS, you can view them Here or download the library Angular JS
React.js is considered the fastest growing JS framework to date: as of today, there are about 1,000 contributors on Github and many users. In MVC (Model-View-Controller) pattern React.js acts as “V” and can be integrated within any architecture. Due to the usage of virtual DOM it provides a great performance boost, comparing to Angular 1.x. In addition to that, ReactJS components can be created and re-used among applications or even transferred for public use.
Despite the fact that ReactJS has a higher learning curve, it makes app development simple and easy-to-understand. Furthermore it can be a perfect fit for complex, high-load and awesome software solutions! Download React JS
VueJS 2.0 was introduced in 2016 and it took the best mixture from React, Angular and Ember, a very handy package. It is proved to be faster and leaner, comparing to ReactJS and Angular 2.0. Going a bit futher, Vue.js offers two-way data binding (as seen in AngularJS), server-side rendering (like in Angular2 and ReactJS), Vue-cli (scaffolding tool for quick start and other things) and optional JSX support. Vue.js is a better choice for quick development of cross-platform solutions. It can become a good basis for high-end single page applications (SPAs) and beneficial solution to those cases, when performance is put ahead of good code organization or app structure or API development. Download Vue JS
Ember features two-way data binding, a bit like Angular.js, keeping both views and models in sync for all the time. So this is very powerful. Applying the Fastboot.js module into it ensures prompt server-side rendering of DOM, improving performance of complex UI's.
EmberJS is commonly usable for complex feature-rich web applications and websites. It is uses on platforms like Chipotle, Blue Apron, Nordstrom, Kickstarter, LinkedIn, Netflix and many others. Moreover it has an easier learning curve and there are oceans of tutorials and guide available online. So this can be the one to build something great upon. Download Ember JS