There have been no studies comparing both head to head. Because I use both, I'd share my experience about them.
The Starwalker uses a long pulse Ndyag whereas other laser machines that do carbon peel usually uses a quasi-long pulse Ndyag. The long pulse Ndyag goes deeper and has even been shown to help with facelifting. The quasi long pulse in the carbon peel can also reach deep to control the oil glands, but does so with the help of a layer of carbon (black carbon attracts more energy and amplifies the quasi long pulse to simulate a true long pulse effect).
I prefer to use the Starwalker because I don't need a layer of carbon and the mess to generate a true Ndyag long pulse beam. Without a layer of carbon, I can also clearly see what I am treating underneath and vary the laser settings if necessary.
As a side note, many places offer a carbon peel and show gimmicky videos of blasting carbon off the skin, but don't run through the heating quasi long pulse step. It is that quasi long pulse step that controls acne, whiteheads and oil glands, so make sure that is not missing in your treatment!
Hope that was useful and all the best!
