Differences ngx-translate vs i18n
According to @ocombe, The idea behind ngx-translate library has always been to provide support for i18n until Angular catches up, after that this lib will probably be deprecated. For now, there are still a few differences between Angular i18n and this library:
Angular only works with one language at a time, you have to completely reload the application to change the lang. The JIT support only means that it works with JIT, but you still have to provide the translations at bootstrap because it will replace the text in your templates during the compilation whereas this lib uses bindings, which means that you can change the translations at any time. The downside is that bindings take memory, so the Angular way is more performant. But if you use
OnPush
for your components you will probably never notice the differenceAngular only supports using i18n in your templates for now, I'm working on the feature that will allow you to use it in your code, but it's still a work in progress. This lib works both in code and templates
Angular supports either XLIFF or XMB (both are XML formats), whereas this lib supports JSON by default but you can write your own loader to support any format that you want (there's a loader for PO files for example)
Angular supports ICU expressions (plurals and select), but ngx-translate library doesn't
Angular supports html placeholders including angular code, whereas this library only supports regular html (because it's executed at runtime, and not during compilation, and there is no $compile in Angular like there was in AngularJS)
The API of ngx-translate library is more complete because it is executed at runtime it can offer more things (observables, events, ...) which Angular doesn't have (but doesn't really need given that you can not change the translations)
This question is old at this point, but I think the answer is in need of an update.
ngx-translate has been largely abandoned. The author of ngx-translate, ocombe, is hard at work at Google to improve the built in Angular method. He transitioned ngx-translate to maintenance only. As of this date (May 2021), he has not done any maintenance on ngx-translate for 11 months including no update for Angular 11.
ngx-translate no longer appears viable for projects newly internationalizing Angular.
I believe that this issue answers your question: https://github.com/ngx-translate/core/issues/495