Yes, I have tried 3 different types of these and have mentioned...

Yes, I have tried 3 different types of these and have mentioned the issuers I have with them above. They do work to some degree as you get some sediment out of them however my issues were/are, If you get only a drizzle of rain, enough to fill the sediment trap the ball then blocks it off, then after this period you get a downpour, all of the sediment is carried into you tank.
Even if the first flush works perfectly as it should, then once the ball shuts off, any following sediment etc is carried also straight into your tank. If you take the ball out, you will find that you will get more sediment trapped.
In the photo I supplied, the wet section causes the water to slow down, allowing the sediment time to settle out and fall into the drain/sediment pipe. This occurs at any time during the rain event be it the first flush, later on or during drizzle or a downpour.
As a matter of interest out of sight in the above photo I still have a first flush diverter which I started with, it holds 40 odd litres. I run it without the ball in it as it is more effective that way.
It gets very little sediment in it now that I have fitted the sediment traps pictured, but as far as I am concerned the more filtration the better.
Of course any filtration is better than nothing.
Does this make sense?