I have Stek on my Alfa 4C. Full wrap. I don't have experience with any other products. My film guy, who also does Xpel, recommended it. It's his current favorite. The top layer is nano-ceramic, so it's hydrophobic, oleophobic, dirtophobic. High gloss and clarity. Washing the car is amazingly easy.
I like it, but if the guy recommended Xpel or Suntek, I'm sure I would have liked them too. OTOH, he might have upsold me on a ceramic coating with the other films.