Sirius Traffic is just another tool that I use to choose a route. Sometimes, it works great. I've avoided some bad traffic while communting to and from Manhattan from Connecticut. Sometimes, it sucks. On Manhattan, when the main arteries that run along the east and west sides (i.e., Route 9A and FDR Drive) are congested, Sirius Traffic will route me onto interior streets that are even more congested, because it apparently doesn't have the data to know that they're worse. I'll plan a route with Sirius Traffic off and then use the NAV with Sirius Traffic on. If I doubt any route changes that it proposes, I just ignore them.
Not to hijack the thread, but I think that Sirius Traffic has a new feature. I haven't been on the forum for a while, so please pardon me if it has been discussed already. I have a 2012 Overland with RHR. A couple of weeks ago, overlay maps with close-up lane diagrams began appearing on my NAV display at turns along the route. When I get off route onto unmapped areas (e.g., parking lots), a big red directional arrow appears to point me back to the route. Here's a photo of one of the overlay maps:
Is this truly new or new only to me?