Obviously you have not spent much time with the 10.5, and certainly haven't compared it side-by-side with the 9.7. The screen is brighter and more vibrant. Plus, the slightly larger display makes it far more suitable as a laptop replacement than the 9.7 ever was.The 10.5 is a sham I see no improvement over 9.7 screen size purely. The 12.9 is still a must have if your planning on doing serious productivity things or if your coming from a laptop with a 13inch or 15 inch screen
That being said, I still chose to upgrade my first-gen 12.9 to the new 12.9 (it's fabulous!), even though I was tempted by the 10.5.