How reliable and accurate is the Tomtom Plus traffic feature for the USA?

I've been using it in Los Angeles for the last couple of days, it does
show traffic activity, but I don't feel it is accurate.

I've been using the traffic featuer for a couple of months in Los
Angeles, The Bay Area, and in between.  It has not just been
unreliable, but has been completely wrong.  I've checked with various
other sources (traffic.tann.net, traffic.com, etc) and their
information alwasy reflects what I am experiencing on the road, but
TomTom traffic almost seems to be random.  Certainly not what I am
experiencing on the road.  The information is readily available and
TomTom has the Traffic very well integrated into the product.  But if
the traffic info is wrong it is worse than no info at all.  I hope
they get it together before my trial period is over.  If they do, I
would be happy to pay for the service.  Currently it is a hinderance
rather than a help.

I agree with the reliability-I have the trial period going on right
now and it is right about 25% of the time-not sure where it gets the
info.