My preference is for Foreflight because the user interface is more readable with less wasted space and more readable graphics. Then again, I almost never use it in flight as I have two touchscreens with just about all the information I need. Also, with a bubble canopy, even with a sunscreen, device readability can be an issue. Mostly, I use Foreflight for flight planning -- weather and fuel prices being the big winners.
One minor advantage of Pilot is that on an ADS-B display, you can tell what kind of ADS-B signal you're seeing -- air to air on which band, what kind of TIS-B, etc. That would have been nice to have when the local TIS-B wasn't working right and the Feds didn't know about it.
Don't know if they've changed it, but on the early versions of Pilot, as you zoomed out, they kept fuel prices for the big city airports, not the lowest fuel prices. Not what I wanted for my flying...
There's a valuable feature that neither one has for selecting stops on long cross country flights -- fuel prices and also available food nearby.
Bottom line is that pilots are adaptable and will eventually get almost anything to work for them.