I came to the conclusion a while back to buy a dedicated unit for each job.
My Nuvi is superb in my car.
My Aera is brilliant for flying with
My lowrance Go2 lasts all weekend walking.
My phone uses GPS for various android apps very well.
"Jack of all trades", where GPS is concerned, does seem to mean "master of none".
But yes, Garmins do seem consistently the least problematic.
That said, if you can cheaply buy a waterproof housing for your smartphone, and possibly install an inexpensive aviation app on it - why not use that as a backup throughout. (Disregarding for a moment that generally there are only two directions on a river, and it's pretty hard to mistake which way you're travelling!)
G