Wait for Samsung Galaxy Tabs S3 or iPad Pro 9.7?

I don't know if this is the right sub or not as I'm torn between both. Since I enjoy having latest tech and either of the both would be my first tablet (and if I buy Apple it would be my first), so is it wise to wait for Galaxy Tab S3? After doing a bit of research I've also come to a conclusion that iOS has apps that are highly optimized for large screens especially iPads that work fairly well with the split screen on iPads and give an overal satsfaction as to media consumtion and business related tasks such as Excel, mail, accessing documents via Google Drive. However after the arrival of Developer Preview for 'N', it seems Google is headed in right direction by introducing an official split screen feature and various tweaks thereby creating a tablet centic OS. Split screen however is not the feature I want and neither I carve for the Pencil but what I really do care about is the OS eco-system which iOS has a clear advantage. It must also be noted that I'm hugely invested in Google environment as I've bought many apps, have all my files on Drive, contact in sync using Google Contacts, browsing activities using Chrome (even though it uses a lot of battery on my Dell), Google Photos for all my casual photo editing and backup and ofcourse have a LG G Watch. Is it still advisable to buy an Apple even though I could use CalDav to sync Calendar and Contacts on iOS, Drive on iPad, et cetra or wait for Galaxy Tab S3 or any other future Android flagship tablet which quite frankly I haven't heard any?