since i have the iphone now i have found the smart GPS in ap store to be reasonably good.
lots of optional stuff to play around with if thats your thing
i used to have " drive here 'on my old windows phone and found that GPS to be very smooth , did glitch a bit at 80 + but that is to be expected when the boat was bouncing about.
I have an Android speed app on my phone that I downloaded just to check the speedometer on my car. Both boats have Vesselview so no need for anything else. My old classic Lyman has nothing, but I couldn't care less how fast she goes.
The Speedometer Free version is what I use for my Iphone as well and it serves my purpose very well. Of course you have to put up with being asked to upgrade to a paid premium version but the free version is plenty capable for my use.