Each has his own merits. Dahang is an American brand, which is hard, valuable, stable in performance and inflated in price.
Ouyama is a brand in Taiwan Province province, and the discount is better, but it is not as good as it looks, and the overall performance is not bad.
There is a brand that imitates big banks called Wolf Road, and there are several UCC models. Wolf Road is a brand in Guangdong, with good cost performance.
Generally speaking, Ouyama is cheap and a little loud, which is recommended by all the big banks. Folding bike is the most popular brand, and other brands have their own brand goods, with good cost performance.
Personally, I think there is nothing wrong with minor faults, and there are quite a few major faults (I use SP8 myself), but Ouyama is just the opposite.