It was good before they switched to subscription
This browser was my main browser and I paid for the premium version which included adblocking. Then something odd happened. The developer name changed but two new "versions" appeared in the App Store. The adblocking function became subscription.
What they did is wrong. Customers paid for a product that never indicated that it would effectively "expire" and no longer be updated.
Da-1510a about
Mercury Web Browser - with powerful Ad Block extensions, v10.0.1