It's a good idea, allowing the cleaner to drip down over the chain as it goes through the brushes instead of having the chain circulate in a pool of cleaner that gets dirty quickly. However, between the third and fifth use or thereabouts the drip mechanism stopped working. The last several times I used it I resorted to just filling the bottom and letting is splash around. I've since ordered a Pedros and will be discarding this one. I really like Muc Off's cleaning fluids and will continue using them but this cleaner (at least for me) is a fail.
This works to get off the obvious grease and grime, but the last time I used it there was residual grease on the chain after rinsing. The screws on the top of the unit are extremely cheap and if any moisture is around they will rust. Absurd to have such cheap screws on a piece of equipment that will be used with liquids. Not very impressed with this product for deep cleaning and its quality of construction. I would not buy it again as it costs much too much money for what you get. I will be surprised if it lasts a year.