Been using the Panasonic red water filter for few years.. its on the more expensive side...
Think the difference is that its supposedly can filter bacteria.. as per the note on the packaging and filter.
That the extra I think from the cheaper Panasonic.
Think what its lacking from the more expensive filter is virus killing which mostly done from the UV light. this one not fitted with UV light.

As for me, old habit .. still boil the water....

Currently planning and saving up to purchase this more expensive item. Mainly for its alkaline and other function. Its an expensive outlay but as comfort its a more premium item. One thing good is that the replacement filter element is just slightly more than the price of the red filter element. So not that expensive to maintain.