I also use the NGA aero app, mostly because I'm a cheap ass and don't feel like forking over $300 a year.
Pros:
Worldwide charts, approach plates and giant reports.
Cons:
Still not user friendly
Does not sync with our onboard wifi (Stratus) like Foreflight does which means the moving map is useless and it can't get you in flight weather.
It has improved quite a bit over the last few years the biggest improvement being able to update all the files through wifi rather than having to download all the files to a computer then having to upload them all through iTunes.
I still think it has a long way to go but considering it's free, there are enough useful features that keep me using it. Plus most of our co pilots have Foreflight and more often I'm flying with someone who has it,