Having had both a 740 and an Ipad, I can say several good things for having the 740 over the IPad
1) You dont have to have one of those dysfunctional, crappy Apple products.
2) The 740 is incredibly bright compared to the IPad not issues with it washing out in bright light.
3) The 740 has jacked inputs and outputs. You can bring in an external camera, listen to music in flight, and you can output NMEA to devices like Dynon panels or some autpilots with very simple wiring. And it uses a standard power cord, ot the expensive and delicate lightning connector.
4) You have a removable SD card for data in a 740, nothing removable in an IPad.
I had a 740 (bright screen version)with a FligthBox Stratux in my old plane and loved it. Everyhting worked perfectly and it fed NAV data right into the HSI fucntion on my Dynons. But the plane and the 740 both got totalled. In my new plane I put in a 12" Ipad with Foreflight for better visibility from a larger screen (I thought) , having synthetic vision, and to get Canadian charts. Not plannign on flying in Canada again anytime soon. So I just got a Stratus 3 and am converting back to IFly as soon as i can get the communication bugs out, and dumping the Foreflight ASAP. As soon as i can find something about the same size with a brighter screen, I am going to ditch the 12" IPad as well. Horrible wash out in bright sunlight and it's an Apple product - what mroe to say.