I use
iNavX on an iPad and
iPhone. Since you are in the US, you will have access to all or at least most NOAA nautical
charts for free. The app is reasonably priced and generally works well.
I use
Fugawi,
OpenCPN, and C-Map's charting program on a
laptop. These apps are generally more complicated but much more powerful with a magnitude of order or so of additional capabilities. The
laptop stays down below but the iPad is in the
cockpit at the
helm.
I also use a
Furuno chartplotter with
C-Map charts at the
helm with a repeater down below.
So, much depends on where you want to access charts, how you intend to use them (route planning,
navigation etc) and how much
money you have available.
If you scan this site, you will find lots of opinions on alternatives.