I am another Ipad in-flight user and am very happy with it.  As others have said, keep it out of DIRECT sunlight.  With the WIFI turned on (required for my ADS-B receiver) it does drain the battery faster.

I researched the literature quite a lot about re-charging and there was a lot of grumbling from non-aviation users of IPad 3 (and newer) when they first came out.   Those people complained that the IPad would no longer charge from a wall charger while being used heavily, and it would never re-charge if plugged into a computer's USB port. The complainers were correct.   BTW a computer's USB port is limited to .5 amp by the USB standard.  The response from Apple was that the newer models use significantly more power than prior versions.  So much more that the Apple standard 10 Watt (~2.1 amps at ~5 volts) wall chargers deliver about the same power back to the unit for re-charge as it is consuming when WIFI is on and the screen is bright etc, etc.  Apple technical people said that a unit with a low state of charge will not re-charge while in heavy use from a wall charger or auto charger.  In order to recharge, the heavy consumption of power must be removed until re-charge is complete. Just closing the lid does that, or the short push of the power button.

So, the upshot for us is, IPad 3 and newer won't really re-charge at all in-flight, but consumption of the battery should be greatly reduced if we use the right charger.

All in all, I can fly two four hour legs and the battery is not excessively  drained, if I plug it into the cigarette lighter with a quality 10 Watt auto charger.  These are 2.1 amp at 5 Volt output. There are dual chargers out there advertising 15 Watts but most are one outlet at 2.1 amps and one at 1.1 amps.  The lower output connection is appropriate for phones or other small devices.  The IPad 3 itself won't consume more than 2.1 amps anyway, so more would not help.