I just started buying some a few weeks ago, it is an acquired taste now. The homemade is meant to be much better than the commercial, so I have ordered some kefir grains to start making my own.
The only thing i have really noticed is that it seems to digest quite slowly, so for me trying to lose weight drinking it in the morning keeps me quite full. with all these things healthy diet and lifestyle changes take time and are not instantly or ever noticeable, they are far too gradual to perceive, and anyone claiming to be instantly feel great is bullshitting (unless they are injecting peds).
However i am mainly convinced that kefir is beneficial so am going to keep taking it, especially for someone who has spent years on a high carb sugary diet and drunk too much to be healthy my gut fauna could probably do with some help. and making my own it is as cheap as milk.
I also fancy starting to make kombucha.