I may have said it earlier. For most who have used a particular EFB for several years and have gotten comfortable with it, I would not recommend switching for a single feature, at least not without taking maximum advantage of the 30 day trial period. These are two excellent apps with 90+% parity in the features pilots use. But the form and flow - the way pilots get to the features is very different.
For a simple example, FF flight planning is primarily based on a freeform planning box on the Map. Add, remove, rotate, switch, and retrieve prior iterations. Pull up, view, add, modify and change. Etc. All directly accessible from the Map. GP flight planning, OTOH, is more structured and mainly based on a UI that mimics what you see in a GTN panel mount (and is actually similar to what you see in a GNS or G1000).
Those types of differences can be no big deal to some, mildly frustrating to others, and a very big stumbling block to still others. If you want a full point by point comparison, it would take a few hours. It doesn't cover SmartCharts, but one you might look at is
@wayneda40's 5-part series ,
Foreflight and Garmin Pilot: Side by Side, where he (FF) and a friend (GP) compare features during a series of flights.