Yes - I do filter my tap water and the reason being that the water is hard with a high TDS [Total dissolved solids] having dissolved organic and inorganic substances in water.
Water TDS level indicates if the water is good for drinking or not. A higher TDS indicates that the water has many substances dissolved in it like minerals, salts, metals, cations or anions in a proportion that the water TDS is higher indicating that it's not good for drinking. Whereas if the TDS level of water is lower this indicates that it has a sufficient amount of dissolved minerals that make it fit for drinking.
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Following is the TDS chart of water - which depicts which water TDS value is good fro drinking.
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In the chart above you can clearly see that a water TDS in the range from 100 - 40 ppm[ parts per million ] is an acceptable drinking water. A higher range of water TDS above 100ppm requires water filteration so that the hardeness of the water can be cut down to an extent that it is fit for drinking. For measuing the water TDS - you can use TDS meters which is easily avialbe in any local electronics shop or purchase online from amazon, ebay etc..
Therefore to answer the second part of your question, it's for the health concerns that I'm using a water filtration to bring down the hardness of the water. Once the hardness of the water reaches close to 100ppm or less than the water taste is also good and is good for health as well. Since I strongly believe in the Health as the greatest asset in my life - therefore it is imperative we take due care of it and since 90% of our body is made of water it becomes even critically that we drink clean and germ-free water.
Answering finally part of your question on a good water filtration product then I would recommend the one which also takes care of making water Alkaline as well. Drinking an Alkaline water has abundant benefits and to name a few they are - instant energy, promotes weight loss, helps fight cancer, helps detoxify the body, Cholesterol reduction etc.. will not get much into it. So, the point I'm trying to make is look out for a water filtration machine that helps making water Alkaline as well.
In my country, I'm using [Dr. Aquaguard Geneus+] (https://www.eurekaforbes.com/water-purifiers/dr-aquaguard-geneus) from eurekaforbes that does the magic of filtering hard water using RO+ UV purification system. I've been using it for Years and found it to be best in class when compared with other water filtration products.