In Apple's defence, a lot of Android tablet apps are just scaled up phone apps - Facebook is the worst. On iPad it makes proper use of all the space, whereas the Android version is just the phone one but... bigger.
The main advantage of the Nexus is obviously the price. When you register your card on the Google Play store you get a free £15 Google Play voucher which reduces the price further.
16GB version: £199.99 (Theoreticall £184.99 with £15 G-P voucher)
8GB version: £159.99 (Theoretically £144.99 with £15 G-P voucher)
My dad owns an iPad but just finds it too big to be practical when out at work etc.
I've had it about a month now and I must say, being able to hold it with one hand and use it with the other is something Apple really needed to clock onto. The iPad mini looks fantastic but it doesn't have a retina display which confused me somewhat. I suppose the reason they've given it the same screen res as the iPad 2 is to save app developers the work.
The Tegra 3 and quadcore on the Nexus make for an insanely smooth experience.