OK I do have some feedback and made pictures.

First of - it works as advertised. But during yesterdays downpoor I noticed that there is little difference when there is very rain. Also it takes much longer for the water to disappear, because the concrete cannot absorb and dissipate the water anymore. I never thought about this - but that is not a bad thing against the product. I will use it for my bathrooms. But for outdoor I will have to think about it. Here are some pics to see how effective the product is after just a single coat.

the lighter are is the treated area in the first picture.

although its applied on a low-traffic outside area it has absolutely no effect anymore. the concrete looks the same as the untreated one. no repelling action either anymore. it stopped having any effect rather quickly.

i did a testing outside first to see how it works. since it didnt perform as expected i didnt bother to use it in the bathroom. when we changed tiles i did use belcem crystal grout though which has anti-fungus & water repellant feature. that seems to be fine so far.