I have used some free nav software and it is ok. I have used it occasionally on an iPhone 3GS.
Certainly not bad for a free app. It calculates the route fairly quickly but its a bit slow reloading the maps when you scroll around or zoom in and out.
It is also only worth using if you have your iPhone plugged into a power source as it goes through your battery really quickly (especially on older phones where the battery life has already taken a bit of a beating).
The only other issue is that there are adverts throughout the app but again its pretty much what you expect for a free app.
Also make sure you download the app at home either over WIFI or via iTunes on a computer as it is well over 100Mb in size so the app won't download over 3G.
If you have iOS 6 or higher on your iPhone then the maps application that is included is actually pretty good as a GPS. It now included turn based navigation including voice instructions and I have found it good. It doesnt include POI or any of those extra features, but if you are looking for a navigation tool to get you from point A to point B then it will certainly fulfill those requirements.
For more detailled GPS features such as POI I personally use the free maps app which seems to work fine. I will warn that it does take a while to start up so as I previously said if you are just trying to find your way to a destination and not use POI then I would stick with the Maps application.
The Google Maps app is also free and offers turn based navigation now as well (although if you have iOS6 then you will need to download this separately as the Maps app is now Apple's own app)
hi... i know this is a very old thread, but this might be of use... i've travelled in the US a fair bit recently, and found CoPilot very good on an iPhone5, and at £7 for the whole of the US, it's a real bargain. The user interface isn't quite a slick as TOMTOM, but at a fraction of the price, it did a perfectly good job.
Before I got a dedicated Garmin unit, I used Motion X GPS. It was decent but I found it a drain on the battery and a pain if you needed to use the phone for anything else (only while safely stopped, of course).
I have played with the Apple Maps gps and it seems "good enough" if you aren't going to use it enough to warrant a standalone unit.
You can download maps for each individual country you visit without paying a penny
I downloaded all maps for central Europe and it worked well. Just like a commercial satnav with voice and arrowed directions
Less reliable for POI's than a commercial satnav but not too bad either
I was very happy with it
It didn't use any of my phone data which I had turned off just to be sure
If you don't have plenty of storage on your phone you could always install the maps as needed.