Best diet shakes? Are they effective?

I have started hitting the gym recently and I don't have much time in the morning to prepare a meal since I commute for like an hour. Are there any good/effective diet shakes? I have read a bit about 18Shakes, but I am not sure if give it a try. I have also heard about Soylent, would this one work or does it has another purpose? Thanks!

Edit: For clarification, yes, my goal is weight loss.