GPS nav in linux is kinda tough.
I tried Iguidance V3 and while it worked in wine, I was not overly impressed.
V4 would not work at all.
I am testing Destinator right now which is pretty good but crashes occasionally. I don't think its run for 60 continuous minutes for me yet.
As for native apps- there are a few but...
My own personal opinion is that Roadnav is the best of the bunch.
The problem with Roadnav is that one way steets don't show up, and very often it sees any lines on the map as roads which cross and can be exited from/entered onto. This can cause problems when you are trying to get on a limited access highway and keep finding overpasses and underpasses. lol
The other nav method I use is Delorme Street Atlas running in a virtual machine: accuracy is top-notch, no crashes but it is just NOT set up well for a small screen. Text entry needs a keyboard and a magnifying glass.
I am hoping for further improvements in Roadnav myself.