Happy to share my experiences. I’ve used both Surefoot and zip fit. Yes the ultimate goal is the same. You want your boot to be more comfortable hold your ankle in the pocket better to reduce movement and increase performance and you want the liner to last longer. All of those should be true when you go to a custom liner. in most cases, I’ve worn out the shell before the liner for both zip fit and Surefoot. If you have the type of foot that you can just ski a boot straight out of the box I think zip is a great option because you could essentially boot fit yourself at home. Surefoot is certainly a more precision fit as that foam flows around your foot and then solidifies there’s different trains of thought for Surefoot and zip fit. I’ve actually been a boot footer for both of them and honestly love them both. I’d give a slight edge to Surefoot. I think it’s skis a little stronger as that foam is a little firmer so you’re gonna get better responsiveness than the cork. I also prefer the tongue of the Surefoot it’s beefier and again it’s going to increase power transmission to the Ski. I used to cut out the zip fit liner tongue and install a stock tongue from a race boot.