I was at the Apple Store and compared the 11" to the 12.9", and my observations are the screen on the 12.9 was significant over the 11.  I did not think the 11" was bad at all.  I think it looked very good.  The 12.9 was that much better.  I will use my 12.9 for some video editing from my drone a DJI Mavic 3 in 4K and 5K when DaVinci for iPad comes out.  The 12.9 is pretty big and time will tell if I like holding an iPad of this size.  I am upgrading from an iPad Air2.  For me, this is a great upgrade.