I have an N10 and my girlfriend has an IPad 2, so I can comment, but its like comparing apples to oranges since the IPad 2 is a year and a half older. The screen of the N10, is so much better, but this IPad doesn't have retina display. I haven't done a side by side with an IPad 4 (or 3) with the retina, but my guess is it would be hard to tell the difference. The N10 has more pixels, but I feel like it would be very hard for the human eye to detect in normal day to day activities.
As for the OS, iOS runs smoother, but like the previous poster said, that's to be expected because there is little in the way of any sort of graphical elements. Moving a grid of icons around is a lot easier than dynamic widgets.
With screen size, the 16:9 or the N10 is a far better experience when using it in landscape mode compared to the IPad, but I prefer the IPad for portrait mode with its 4:3 screen. The length of the N10 in portrait can just seem awkward sometimes IMO.
As for apps, there is no doubt that there are more IPad specific apps than tablet apps for Android. You always see the 275,000 or whatever IPad apps vs. Android's unspecified number of tablet apps. From my experience, I haven't run into too many issues. Yes there are some apps that need to run in phone mode, so the UI is far from nice looking, but at least you can use it. There are a ton of IPhone apps that just aren't available for IPad.
One thing that I do want to note is browser performance. I've been pretty disappointed with browser performance with the N10. Chrome, for me, is almost unusable. It laggs A LOT. I've tried other apps like Dolphin Browser, Firefox, Ocean Browser, and my current, Boat Browser, and they are better than Chrome, but still not as fast as Safari on the IPad. I'm hoping that upcoming updates to Chrome increase performance.