I've used the Bigen Cream Color 4-0 Dark Brown a couple of times, and while it's effective at covering gray hair, I found the color to be slightly dull. It's an okay choice if you're looking for convenience, but I prefer a more vibrant shade.

The Bigen Cream Color 4-0 Dark Brown is a good option for covering gray hair quickly. It's easy to use, and the color turns out nicely. The smart saving feature is a nice touch too. Overall, I'm satisfied with this product.

I'm loving the Bigen Cream Color 4-0 Dark Brown! It's easy to apply, and the color comes out beautifully. My gray hair is completely covered, and I appreciate being able to save the leftover product for my next touch-up.

The Bigen Cream Color 4-0 Dark Brown is a reliable choice for covering gray hair. The application is quick and easy, and the color payoff is impressive. I've had great results with this product, and the smart saving feature is a nice bonus.

I found the Bigen Cream Color 4-0 Dark Brown to be a decent option for covering gray hair. The color turned out fine, but I didn't find it to be anything special. It's an okay choice if you're in need of a quick touch-up.