Should I use filebeat or an app-logging module with lumberjack capabilities to collect my logs
Both are common and comes with their own pro and cons.

It depends if you can accept loosing logs if logstash is dead and your app restart and on the other hand if you can write logs to disk and consume place there.

Those are the basic points to choose for one or the other, you may end up with more caveats in term of IO/caching/etc.

There's no 'best' option, there's the best option for your organization/teams which we can't answer for you as we don't know your environment.