Plant-based milk behaves differently in coffee than dairy milk does, mainly because of two things, protein content, which affects how well it froths, and how it reacts to acidity and heat, which affects whether it curdles. Knowing these differences up front saves you from a few disappointing cups while you figure out your preference.
Oat milk has become the specialty-cafe default for a reason, it has a naturally creamy texture and a mild, slightly sweet flavor that does not fight with coffee's bitterness, and its starch content lets it steam and froth reasonably well, closer to dairy than most other plant milks manage. Barista-blend oat milk in particular is formulated specifically to hold up under steam wands, with added oils or stabilizers that improve texture over a standard grocery-shelf carton. Sprudge's explainer on oat milk covers why the barista versions behave so differently from the ordinary ones.
Almond milk is thinner and lighter, with a distinct nutty flavor that some people love and others find competes with coffee's own flavor. It froths less reliably than oat milk because it has less natural fat and protein, so if you are making a latte at home with almond milk and getting flat, watery foam, that is a known limitation of the milk itself rather than a mistake in your technique.
Soy milk has the highest protein content of the common alternatives, which historically made it the best-frothing plant milk before oat milk's rise, and it still froths well today. The tradeoff is that soy milk is the most prone to curdling when it meets hot, acidic espresso, particularly with darker roasts or lower-quality soy milk, so if you have had a curdled soy latte before, that is a real, fairly common chemistry problem rather than a fluke.
Coconut milk brings a distinct tropical flavor and a rich mouthfeel, but the canned, high-fat version is different from the thinner, carton version sold specifically as a milk alternative, and only the carton version is really meant for everyday coffee use. It can also be prone to separating in hot coffee if it's a lower-fat or additive-light version, so barista-formulated coconut milk blends tend to perform more reliably than a generic carton.
If froth and texture matter most to you, reach for a barista-blend oat or soy milk first, they are formulated specifically for that job. If flavor neutrality matters more, so the milk does not compete with the coffee, a light, unsweetened oat or almond milk is usually the safer choice over anything sweetened or flavored, since added sugar and flavoring changes the whole drink's balance in ways that are easy to accidentally overdo.
None of this is about one option being objectively better, dietary needs, allergies, and personal taste all matter more than froth performance for most people. If you are experimenting for the first time, buying small cartons of two or three options and testing them side by side in the same drink is a more useful way to find your preference than reading any single ranking, including this one. Morgan Eckroth has worked through most of these from behind a bar on camera, which is a useful sanity check on how they actually steam.