I have the R2Hv with the built in GPS although the GPS works fine I'm not real thrilled about Streets & Trips 2007. Right after I purchased the R2Hv we went on a vacation and I had my route all setup.
During one of the trips in a busy downtown area I got caught in traffic and missed a turn, that's when I found out the Streets & Trips won't re-route to get you back on track. My first GPS, my first lesson!
Maybe I'll win the next iGuidance contest if I don't buy it first.