I've used Gulp in the past - it's a subscription service, €15 per month and they change the filter annually. It makes the water taste better but if there was for e.g. a boil notice, you would still need to boil. I had to put this in the utility as they wouldn't put a hole in my kitchen worktop (granite).
This year we switched over to a quooker tap and although it's a lot more expensive, I am loving boiling and filtered water on tap. There is also an option for carbonated water but that pushes the price up much higher. After installation you pay approximately 300 a year for the filter cartridge, so it's more expensive to maintain than Gulp too.