js-to-do | A Simple To Do Web App using just JavaScript | Animation library

Due to network and io limitations, there is no reason to choose a method in your case based on "speed". The download speed and write speed is out of your control (programmatically), leaving just the speed of the individual methods themselves. Since networks and io have a maximum speed, using the method that executes fastest isn't important because said method will ultimately be throttled by the network and/or io anyway once you start looking at downloading multiple files.

Use the method that makes more sense for the situation. In your case, if you're trying to download files with node, it makes more sense to me to use node.js to do it rather than wget with a child process.