One of my trips to France before christmas was in the C55. As I had a Tom Tom (for use in the van) I took it with me and decided to use both to see how they compared to each other. Putting aside the asthetics of trailing wires and separate screens, here is how they performed. The comand calculated the 541 mile trip quicker. they both chose pretty much the same route except when deviated from the main Peage. It was at this point that I arrived at a T junction and one said go left, the other go right! I went with comand and the tom tom quickly recalculated to compensate after about 50 metres. What I did notice though was the Comand voice was nicer than the standard female Tom Tom voice. Both showed an ETA within a minute of each other. Both showed remaining distance within a couple of miles of each other. The comand had TMC which showed congestion the Tom Tom didnt. The Tom Tom alerted me to the presence of speed cameras the comand didnt/couldnt. The only glitch with either was the Tom Tom occasionally told me to turn around on a slip road! So its a close call on Navigation. However, when I had an incoming phone call the comand went silent. The Tom Tom didnt and I had this person bleating on and on at me whilst I was talking! For me, trailing leads and separate screens are a pain and unsightly. But the speed camera alerts were useful.