I was split between the 10.5 and 12.9, as I prefer the size of the 10.5, but I just saw on Twitter that Serenity from iMore confirmed that when using 50/50 split, the 10.5 uses the apps iPhone UI, and the 12.9 uses the iPad UI for apps. This may be a deal-breaker sadly. Split screen work is something I'll be doing a lot of. Admittedly I don't have any experience with 50/50 on a 9.7, and have only used it on a 12.9 in the Apple store, which I liked. So I'm wondering, how big of an issue is this actually, and is this a deal-breaker for anyone else?