This topic is interesting in that the answer is not black & white.  There are times when a GPS app in a cell phone will be more than adequate, downtown making decisions on where to have dinner before the movie -- critical issues like that.  
For anything backwoods or survival oriented, a stand-alone unit (with or without maps for those who carry paper topo maps) or with full mapping capability for those who don't, is the way to go.  My primary is a Garmin GPSMAP 60CSx, with both street and topo maps loaded.  If it's a planned outting, I'll also have paper maps for the area.  
I'm biased though, a Garmin Nuvi on my dashboard, a 60CSx with my gear in the truck and a Geko 301 in my EDC backpack as back-up.  But I like knowing where I am and a cell-phone GPS is not for serious navigation.  
YMMV
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Better is the Enemy of Good Enough.  
Okay, what’s your point??