Note: info is outdated. At this moment we use PinoJS and couldn't be happier. PinoJS is basically a better (cleaned and tuned) version of Bunyan logger used by NodeJS team.

The abscence of feature is not automatically BAD just and the presence is not automatically GOOD.

https://npmcompare.com/compare/debug,log4js,winston

• Morgan – purpose? Trivial to implement on top of selected logger.

• JSON logging – arguable.

Initially I felt like Log4JS has better defaults so decided to stick with it. Then I've found a significant drawback: Log4JS wants you to attach transports (called appenders there) to categories rather than loggers themselves. So you cannot define levels per transports per loggers.

I may be wrong, but I belive this (basic) case is not possible to configure with Log4JS:

WINSTON
  mainLogger
    transports
      console
        DEBUG
      file  
        INFO
      SMTP
        ERROR

Winston also understands exceptions so

try {
  throw Error("bad")
} catch (err) {
  logger.error(err)
}

logs valid JSON (note \n) (plain text is also configurable).

{"message":"bad","stack":"Error: bad\n    at Object.<anonymous> (/.../test/winston.js:14:8)\n    at Module._compile (module.js:573:32)\n    at Object.Module._extensions..js (module.js:582:10)\n    at Module.load (module.js:490:32)\n    at tryModuleLoad (module.js:449:12)\n    at Function.Module._load (module.js:441:3)\n    at Module.runMain (module.js:607:10)\n    at run (bootstrap_node.js:382:7)\n    at startup (bootstrap_node.js:137:9)\n    at bootstrap_node.js:497:3","level":"error","timestamp":"2016-11-07T09:28:41.799Z"}

Usage experience: Winston is hands down better than Log4JS in almost all aspects.