Huh. They claim they’re tested by a lab that does NSF testing, but they don’t appear here:
https://info.nsf.org/Certified/DWTU/
Also, its’s expensive.
I consider this to be a baseline:
https://www.3m.com/3M/en_US/p/d/v000517548/
It’s genuinely NSF listed, varies from about $40 to about $60, and has pretty good throughput.
For anything fancier, I would either get an RO system with a permeate pump (and I would absolutely do this if I lived somewhere with annoyingly hard water) or a commercial system. Check webstaurantstore.com or similar.
If you have a dramatic taste improvement with filtration, you probably have chlorinated water. IMO it tastes nasty, is easy to remove, and is harmless to drink at normal concentrations if the chemistry is right. Lobby your utility to switch to chloramine for residual disinfection.
(If you spend time around pools, you might be familiar with these compounds in a swimming pool context. Chlorine has a mild clean smell, and many people don’t love it in their drinking water. Chlorine plus many organic things turns into monochloramine, dichloramine, and nitrogen trichloride. These are collectively called “combined chlorine”. The latter two are utterly disgusting and possibly quite harmful, and the nasty “chlorine” smell in less well maintained pools, especially indoors, is those. Pure monochloramine is inoffensive in reasonable concentrations.)