I'm not big into vegetarian substitutes but oatmilk is legitimately delicious. It's good for lattes, cereal, whatever. I guess maybe not good for baking?
The thing that gets me is that the price of oat milk is so completely divorced from what it cost to produce. It's absolutely wild that oat milk, made with one of the cheapest bulk grains, is as expensive as almond milk, made with an expensive nut.
Almondmilk is mostly water and thickeners. A typical 32-oz carton uses around 12 almonds. You can tell by the protein content of all of these altmilks how cheap they actually are to make.
The only exception is soymilk which does actually have a lot of protein and also has a really long tradition. People have been making soymilk for over 2,000 years. American grocery store soymilk is quite different but you can actually go to an Asian grocery store and still find soymilk that has a single ingredient.
Here in Europe we can fin the single ingredients soy milk if you look down the shelf: the cheapest brand and groceries have no additives while the fanciest ones are full of thickeners and various sugars. I recommend the store’ brand from Carrefour, Lidl and Leclerc.
I will say the quality of single-ingredient soymilk varies greatly. There's definitely a skill involved. I try a lot of soymilks and the best soymilk I've ever had and the worst have both been single-ingredient
For baking: depends on the recipe. In one recipe of a sort of muffin style bread that uses egg to rise (no baking powder, yeast, etc), oat milk makes it not rise properly and you get dense bricks instead. Other recipes have been fine. YMMV.
(Though, I quite like the non-homogenized full fat milk with bits of thick cream floating on top too. Oat milk, while pretty good, got nothing on that. Perfect on the porridge for breakfast.)