Splitpush or Group ? THAT is the question.

Group? Is that a thing now? Kids and their fantasies. ...

It depends entirely on which champ you are playing and which lane you are splitting. For example, if you are playing Shen, and the rest of your team is bot lane, splitpush top. Why? You can easily take a tower and if they don't take away at least 2 to stop your push, you can just keep taking towers. Also if they try and engage your team you can easily ult in and you are back in the teamfight. Most champs cant to this and rely on TP / communication on ward placement to make this happen efficiently. If you don't have TP or an ult like Shen / Panth / TF, just group FFS. :)