WHAT ARE THE BEST WATER FILTERS/ COMPANIES FOR THE KITCHEN FAUCET AND SHOWER THAT ARE EASY TO PLACE (DO NOT REQUIRE A PLUMBER/ ARE NOT UNDER THE SINK)? 

I primarily concentrate on comprehensive whole home solutions and I am not as well-versed in DIY systems. Nevertheless, a system such as iSpring, featuring a multi-stage activated carbon block filter and third-party testing to comply with NSF/ANSI Standards, is generally considered a reliable model. 

When considering a shower filter, I would recommend seeking similar qualities. Look for a system that incorporates a multi-stage filtration process and has undergone third-party testing to meet recognized standards, ensuring its reliability and effectiveness.