I think both TomTom and Navigon are crap at categories when it comes down to searching the POI's. IMHO, the only difference I have noticed is that Navigon (Navteq) has the POI data and TomTom (TeleAtlas) doesn't. Honestly, what I've noticed is that TomTom is the one that needs the Google search since the lack of POI's. There must be huge differences in regional data.
Honestly I have to say its a tossup. I always test POI DBs by throwing a handful of places I go to frequently at it. I'll try a mix of restaurants, hotels, shopping centers etc to see how easy it would be to find these if I didn't know the area.
I have to say as far as POIs being in there, it is a tossup. I like the way Navigon allows you to zoom in and out of the minimap. Helps me to see if the POI I've selected is indeed the one I want before navigating to it.
However, ever since my Navigon 8100T the city name thing was a real problem. on the 8100T PND it was easy to fix though, I simply changed the config file to make "nearby" be 50 miles.
On the iPhone program having to know the exact city name as it appears in the address is a MAJOR MAJOR problem IMO. Like the example I gave, even if you know the name of the POI exactly, unless you search the exact correct suburb name you ain't gonna find it... even if its in there.
It seems that Navigon makes its query look something like this:
select POIs from POIDB WHERE City = "Whateveruserputin"
whereas TomTom's query is more like this
select POIs from POIDB WHERE POI IS NEAR("Whateveruserputin", 100 mile radius)
Is that restaurant my friend invited me to in Westlake or Avon Lake? hmmm lets try Westlake... nope. Lets try Avon Lake... nope. How about just Avon... aah there it is!
That scenario is much less of a pain in the ass on the TomTom.
Again, my gripe is not the contents of the DB. I think Navigon and TomTom's POI DB are sufficient for my purposes. The implementation gets me.
PS. If I'm in a strange city not looking for a specific POI but rather just browsing... I prefer Navigon because of how it groups POIs by major Chains.