Personally, as one who wears UK 6F in AS, I find it to have good room a the ball with a tight waist and good heel cup fit. For the price, it is a good value. They are just gaining steam since they had some organizational changes many years ago but for the past few years they have established a good business model (at least from my perspective as a customer). Their leather is not as nice as G&G and their burnishing is not as creative as EG, but again, those are hundreds more in comparison.
I definitely prefer AS over Carmina (I've never owned Meermin so I cannot comment) but it's just my preference towards "sturdier" feel of shoes. Vass is an interesting comparison since they cater to a different look I think. My issue with Vass sometimes is that they are not as consistent with their final product (which is to a point expected with their manufacturing model).
Although I have a number of JL, I do find them overpriced for stock shoes.