I’m not a fan of soy milk; every version I’ve tried has an aftertaste I can do without. Almond milk has been my go-to for cereal and cooking for quite some time now, and I’ve had a lot of luck with it thus far.
However, I’m game to try anything that isn’t directly dairy, because me and the cow version just don’t have fun together–hell, I haven’t had “regular” milk in years, at least not in it’s straight form, and I haven’t missed it one bit. Even so, I’ve met people who swear by soy milk and can’t stand almond milk.
That said, eating a more plant-based diet often means sifting through the available options, and finding what works for you. The article linked here does a fairly decent job of hitting the highlights of what’s currently out there and the benefits of using each, but I always suggest doing your own research–and using a little trial and error–to really find the one (or two) that make your non-dairy life easier.