The Nexus 9 is larger than the RMini. At 228.2 mm it is 28.2 mm wider than the mini (can it be held with one hand like the mini?), made of plastic casing, the screen has lower ppi (we do not know what the gamut looks like until there are reviews), has only 32 gigs (the mini has 64 and 128), and has less battery time.
The battery time and the storage are very important to me.
I really doubt that the Nexus 9 is similar to the rMini.
I see your point. There are no other 7.9 inch 4/3 aspect ratio tablets on the market...however, the Nexus 9 is very comparable to the Mini. The Nexus 9 (at 8.9 inches in 4:3 aspect) sits almost right in the middle between the Mini and the Air and the size is very compelling. Neither the Mini or the Nexus 9 can be "effectively" held in one hand (i.e. palmed). Maybe Sasquatch could pull this off...but not us mere mortals. Plastic casing is on the Nexus? Fantastic...means I won't have to buy a back case, which I've always had to purchase for the Mini. No, we don't know what the gamut looks like yet on the Nexus, but we know with almost certainty what the display will look like on the Mini 3....same 63% gamut and muted colors. Nexus having only 32GB....works for me! Battery time on the Nexus is stellar as with the Mini.
However, my point is that Apple has left me with no viable option based on my needs and what I value in a tablet. I'm not going one more round with Apple by purchasing the Mini 3 when they are not even trying! I'd rather go with someone who is at least making an attempt to deliver best in class technology. Now, this is from a person who has a 27 inch iMac, 15 MBP Retina (for work), iPad Air (my Wife), iPhone 6 plus, multiple other apple devices and services (ie Nano's, Shuffles, iTunes matching, etc, etc..etc...). The point being, it's not an easy escape to make from the Apple eco system. But I'm willing to make the escape if I see the better value elsewhere (i.e. which I do at the moment) and am left with no viable options to stay!
Now, if the Air 2 ends up having 2GB RAM, I may go that route, even though I much prefer a more portable tablet, as it will give me at least one viable option to stay in the Apple Eco system (i.e. Extra Ram would add longevity). We'll know the answer to this early next week.