True there are many on the market. The reason I use the Clear 2O system is that it uses a force feed system, (the water is forced into the filter), rather than using gravity to let water slowly drain over the filter. Also it was a prototype water pitcher filtration system that was being marketed here in Toronto back in 2007. Looks like they have a gravity version one as well which is new for them. Brita is a gravity fed water filtration system, and everyone is familiar with how that works and is available everywhere.
I've had mine since 2007 with no issues. The one disadvantage is that you have to get replacement filters online, as there are no retailers that sell them, at least not here in Canada.
There is also Katadyn https://www.katadyn.com/us/us Yeah it's more for expedition / disaster type use but I am sure you can find something of use like water treatment for example. I use their Hiker Pro water filtration system when I go camping and is handy when water is at a premium, like when an urban disaster hits or when the municipal water treatment system is down.
Yup, I have some experience in this sphere and can share with you some advice. To find a good filter nowadays is really hard, especially if you want to get a good service. We tried to use heads for taps, plastic filters, but nothing worked well, there appeared bacteria and algae. We have found solution in water softeners San Diego. It is a whole house water filtration system. This service provides very long guarantee, think that it is sign of high quality. On their website there are a lot of certificates which confirm it