Navit on the N900 is not as good as the Navit imlementation on an Android device. But considering all the other GPS options for the N900 that are decent are either online apps, comercial or both, it not too bad.

Major bugs/problems are;
1) OpenStreetMaps will peg streets to the nearest town name (& some of them are obscure, out-dated or wrong)
2) You are limited to the onscreen keyboard within Navit & it is buggy (doesn't update cases, #s, etc)
3) Synthesized voices are not always clear
4) Routing will sometimes force you to go the long wayaround, rather that identify shortcuts.

Other than those, it's great.