I still think it's better to leave SBCs behind and get a refurbished Dell. Cost is nearly the same as inflated pi costs but power is stable, more faster cores and more memory.

But if you must go with SBCs just for small form factor / cutefactor reasons...

RockPro is decent, but these days I'd recommend getting an SBC with at least 8GB of ram

https://hackerboards.com/?exclude=discontinued&memory_max=33

I would stop buying Raspberry Pi's if I could find one in stock to refuse to buy.

I've been thinking of getting a Beagle one/BeagleBoard or some other SBC from Texas Instruments since my first computer was a TI 99/4A. It is disappointing that there aren't as many cool projects for Android as there are on Raspberry Pi's.