I have bought two of them and I'm using them since more than one month. It is quite early to say they will maintain the promises but Up to now I'm very confortable with them.. they appears of good quality and are very easy to calibrate and to program.
Above all, after one month of use, the differences in the dosing are quite negligible. This is one of the main strength of this product.
If you are looking for a simp,e way to dose additives to your tank with hygh dosing stability and flexibility in the positioning of small boxes this could be your product.

A little too noisy compared to my other dosing unit, but other than that, its good value for money. I particularly like the fact that it can be calibrated.