I bought an orange pi (still in the post from China) but from all I've read I'm wishing I hadn't.
Sounds like still very flakey support in the mainline kernel so most are using hacked 3.something kernel.
Also, although it has twice as much ram as a pi 3, it uses, as you mention a cortex a7 to the pi3's cortex a53 which from all I can tell absolutely smacks the little a7 to pieces.
You've quoted the lie the xulong keep repeating about the chip being 1.6ghz. It's not.
1.6ghz is a factory overclock on their own dodgy linux distribution.
The SATA port sounded like a nice idea for a little file server but the SoC doesn't support SATA so it's just a little USB to SATA bridge built in which apparently performs horribly compared to the ones you' get in your average external USB hard drive.
So worse hardware, more expensive, less software support, mali gfx that will never make it to the kernel.
If I knew what I know now, I wouldn't have bothered ordering one.