It’s a case of “Your results may vary”. The filters are there for you to try if you notice needed improvements or to just play around with them to see if they do make a difference. But the variables are too numerous to say one filter will work in all or most cases. (There may be one or two that do but I haven’t yet heard a general consensus to that effect yet.)
I remember someone stating it this way... Set up a filter and take some measurements, signal strength, etc. Then move that scanner to another location and take the same measurements. They won’t be the same-they can’t be because your location has changed... and with that, your choice if filters most likely will need adjusting to another filter or none at all.
I don’t use the filters but have played with them just to see if they might make a difference. Apparently I didn’t have any of the issues that caused Uniden to make them available for the end users so, in my case, they aren’t needed. But I don’t suffer from simulcast, which I believe is the main reason Uniden made the filters available. I could be wrong on this point. If I am, so be it. Maybe there will be other reports from those who notice an obvious improvement when filters are used.