I bought the 11 soon after it came out, and then started thinking about the 12.9. After endless visits to online reviews, message forums, and stores, I bought the 12.9 when Best Buy recently discounted it $200. My plan was to use the 15 day return window to compare with the 11 and then decide. That came & went, and I now have both iPads, and am happy with my decision. Am not a power user, not a student, just a soon to be retiree who enjoys both for different reasons.
My 11 stays on the sofa & recliner (and occasional trips to the bathroom). Also goes with me when I travel. At home, I enjoy researching TV shows or movies while I watch as well as doing emails and reading digital newspapers during baseball or football games, etc.
The 12.9 stays on the dining room table and is primarily used when I want to read the full digital newspapers or any of the 55 magazines I follow on Apple News+ and also for looking at financial pages. It's almost like viewing the actual magazine page, which I like.
Of course I know it's not cost effective, but I got each of them on sale, which softens the pain.
Once you spend time with the 12.9, the 11 seems so small...but that's what makes it great for the sofa.