Well my verdict after about 10 days use of the MK3.
It is an improvement for me!
As stated above, it reduced my maximum data rate both for download and upload. The sync on upload is now a little below 19999, but my download is capped at 59999 which is still below the (reduced) line maximum. So no change in speeds really.
But there is a real reduction in line disconnects. With the MK2 it used to resynch a couple of times a day (I live near a tube line), but now it has only gone down when there was a thunderstorm. My noise margin for a given maximum data rate has increased and my line attenuation has fallen slightly.
So it suits my line, but as I say I have known REIN issues, so maybe that is what this new filter is good for.
Edited by Colin_London (Tue 14-Oct-14 23:00:03)