Have had good luck with ZeroWater which comes with a TDS meter on the pitcher. Unlike Brita indicators which are time-based, this allows you to just measure the solids have actually been removed (if it's too high, it's time to replace it)
Zerowater is great but man their expensive filters do not seem to come near the advertised amount. The expense and lack of good third party alternatives for their filters just adds salt to the wound(since it didn't get filtered out HA!).
What is the appeal of these compared to just getting a 10 inch under the counter filter set? I have a double filter set, with two different multistage filters. The water is extremely well filtered and it's relatively cheap to change the filters a couple times a year as per manufacturer recommendations. It took me 35 minutes to install, but it's been running fine for years.
You make a good point. I'd imagine the large upfront cost + the effort required to install.
It is not expensive - even when compared to pitchers -, and I guess perceived difficulty, since it is not hard to install.