I use a Nexus7 with Skydemon. After last week's update, it performs flawlessly (scrolling was a bit slow before). I never had a drop in GPS signals using the internal GPS receiver. The size and picture quality are perfect for cockpit use.
Remember to turn off the GPS when not using it since it draws quite some power.
I have about 25 hours with the combination since April, both IFR and VFR. There is a new version of Nexus7 (FHD?) coming out right now, but older versions can be had for less money.