it's a toy, don't think it will replace your GPS. We have to wait for proper software.

I did some km with n900 as a gps just for a test. I've downloaded all maps etc.

GPS signal, for me perfect
Maps...well...another story.
1) Not that detailed, some roads are not there etc. I know Ireland might not be the biggest market but...
2) Keeps asking for INTERNET connection! Then it will stop and...after 20km it will try to ask again...10 times! What part of NO you don't understand!
3) No automatic recalculation.
If you take the wrong turn go back to 'selecting start point' and click again 'from gps position' and magically it will recalculate.
4) No navigation - you have no idea how far you have to go before next turn so you keep staring on your phone from time to time or you have to zoom out to have some idea when is the next turn

Again...nice toy, don't use it because you will crash, get lost or start screeming in your car: NO I DON'T HAVE INTERNET CONNECTION. Trust me