I have recently purchased the sat nav application directly from the SYGIC website costing around £42.00 GBP and i must say how impressed I am with it.
I previously had a XDA ignito (HTC Diamond) with TOMTOM 7 installed and i would say this equals it.
Easy to use and setup
Works straight away, the phone takes less then 10 SECONDS to obtain a gps fix from cold - even quicker when hot. That is much faster that the diamond.
If you tilt the phone sideways SYGIC automatically turns as well without having to exit the program or mess with settings.
When you switch it on there is a H&S warning about driving whilst using a mobile, this comes on everytime and cannot be switched off, Annoying!!
The voice actually says the road names, in the case of the A4123 it should say "TURN LEFT ON TO THE A FOUR ONE TWO THREE, but intead it says "TURN LEFT ON TO THE A FOUR THOUSAND ONE HUNDRED AND TWENTY THREE"