The only navigation app I've used with it is Waze. It's free, so that makes it 100x better than the NavGate ones Pioneer flog for £80. Try Waze for your phone to see if you get on with it...if you do, it's pretty much the same on the HU, bar one or two interface issues. There was a real low point recently where you couldn't enter an address on the head unit, but Waze have at least one dedicated beta tester for the Pioneer units now, so that kind of cock-up should be a thing of the past.
As with anything, try before you buy. My experience with the radio has been usually good, with one or two frustrations. Some of those were caused by a faulty cable, some of them by dodgy updates. When it works, which to be fair is 99% of the time, it's a good unit. Sound-wise, it's way ahead of the RCD-300 it replaced, and the novelty of being able to run a browser or something like DashCommand is worth the occasional glitch.