Total piece of crap IMHO !
I've read the manual, watched the videos, did everything that I could... It looks really good on paper, but does an awful job in real life.
My experience is just the same of all the fellas above... I just think that the "40nm thing" is way too close !
Sometimes the bloody thing shows HUGE formations at 80...100nm, which makes waiting for the 40nm threshold, not acceptable to start deviating. If the displayed weather is REALLY REAL and you wait that far, you'll probably end up turning 90degs from your route to avoid. And I'm not event talking about how it changes it's mind at every scan...
I often set my side to manual mode (usually 4000ft...5000ft bellow the CRZ FLT LVL) and even like that, I feel that the depicted weather becomes accurate only when less than 40nm from it.
I really feel glad when I board an acft equipped with the RDR4B ! That's definitely a radar you can trust...
It's "great" to watch (FlightRadar24) how different are the deviations of acfts equipped with the RDR4000 x RDR4B !
But... What can we do ? I think that the best option is get used to it and understand that we'll be requesting a lot of deviations which wouldn't be needed if using another radar !