I copied my response from the RL thread and started it here because the issues apply to both of my cars:
This is in response to my previous posting: I have subsequently re-enabled Traffic on my RL and Traffic and Weather on my MDX but I stand by my previous posting. I did this because the systems have the potential of being great but the implementation is so bad that XM should be embarassed to charge money for it. In fact, I got both cars for the $77/yr but the optional Traffic and Traffic and Weather Doubled the price!
I drove to work this morning and the flow was green but a freeway to freeway interchange was completely closed and the system did not show anything. I realize that it will only show reported problems but if nobody reports to XM it doesn't seem to stop XM for charging for something that they must realize is useless.
Every other source of traffic is better than XM's and is free so I have to conclude that Traffic and Weather are the slush fund that XM uses to pay off its lawsuits.
Last weekend I was skiing at Mammoth mountain CA and the MDX Weather said Snow AM and PM for 2 days. Needless to say, it did not come close to snowing on either day, in fact I'm nursing a little sunburn! Again, as previously stated, you will get a more comprehensive weather forecast by looking out of the window.
In conclusion: if Traffic and Weather were free it might be worth it to pretty up the screen but the real info is from numerous online sources and it is already free.

 

I have never had a problem with Nav Traffic, in fact there are times I will think the system is wrong and lo and behold it is 100% accurate. However, I must qualify my comments that my experiences are mostly in smaller metro areas with the exception being Chicago. I had a recent experience in Chicago where the system told me to take an alternate route thru downtown and I didn't heed the warning and paid for it by being stalled in traffic for over an hour. As for Nav Weather in my MDX I say that Acura has missed the mark as far as forecasts for local weather, both at the 1 and 3 day levels. Other car companies use the same service and provides its customers with current temps and conditions, but the service is much more expensive as they use different hardware and software. The Nav Weather does shine (pun intended) for the radar map, which is my favorite feature. All-in-all, I like both services, but I agree they are overpriced, but that is more a problem with SiriusXM than it is with Acura, who equips all it's vehicles with the receivers whether or not the owners use the services as does GM with its OnStar system.