Cleaner, Yes. Pure water, No. Clean water is almost a science in itself. A 5 micron filter comes with the housing. That will remove quite a bit of sediment, but by no means will it get everything. You then need to consider how clean you need to make it. City water is usually treated to kill anything alive in the water, so you only need to remove the sediments. Your water department sends out a report from time to time with more information than you need, but it tells you what to expect.
Well water needs to be filtered and treated to kill bacteria and viruses. They are as small as .01 microns and cannot be filtered out. That's why water is treated to kill them.
To a certain extent. It removes sediment very well and does extend faucet and plumming equipment life. However, it will not remove lime from hard water. You need a water softener to do that. That being said, I have used this type filter for 20 years and have been very satisfied with the results. If you have a 'smell' problem you can use the carbon filter to allieviate that.