I was a bit of a collector/hoarder of SBS’s up till quite recently…
TL;DR - there’s a good reasonably comprehensive list of SBC’s with reasonable “support” at https://armbian.com/
My collection :
10x NTC CHIP (Kickstarter project and company now defunct) - pretty much like an RPi ZeroW - the best thing about them was solid power-management (i.e. built in LIPO charging), plus good community and vendor support - and they were only $9 each… and the vendor did a fair amount of work on the Linux kernel for them, GPU support, recent kernels (4.11 I think?). One pitfall with them in my experience was the storage was onboard NAND and I’ve found it a bit flaky - MicroSD slot from the start would have been better. They also had PocketCHIP which was a pretty awesome idea (I bought one with my kickstarter reward).
2 x Pine 64 (from Kickstarter) - they’re pretty much garbage (so called gigabit pretty flaky - different MAC address every boot) - the support from the vendor is non-existent, best O/S for them is Armbian (and while I’m there - here’s a plug for Armbian - I’ve kicked them over some money in the past 'cause it’s a great project - check them out - https://armbian.com/ and there’s a good list of SBCs on there). Also Pine64’s forum is run by a bunch of Nazi admins…
1 x BananaPI - pretty “okay” bit long in the tooth - but works okay - also has battery charging circuit (have to solder leads onto the board) - I run Armbian on mine. Only 100 Mbit.
1 x Oranage Pi 2E+ - quite pleased with the specs on this board, I run Armbian on it - but there’s no battery support. “Proper” gigabit.
2 x RPi 3B - these are okay - I run Raspbian “stretch” on both - I keep one at work on my desk (I’ve got about 300 or more RPi to support for one customer) - but the thing lacking is no easy lipo battery path to make them portable - the other one runs 24x7 as my SSH jumphost to my home network from “outside” and I run Pi-Hole on there.
If powering / charging a LIPO was easy with RPi ZeroW I’d probably grab a couple of them…
I saw a neat looking SBC (hex core 64 bit ARM 4 GB RAM) Indiegogo project “Renegade Elite” - but they never reached their funding goal - so I don’t know if it will go ahead : https://www.indiegogo.com/projects/renegade-elite-the-revolutionary-mini-computer#/
Beware when shopping around - many of them have REALLY crappy vendor support - take for example the Pine64 - it’s running an ancient 3.10 kernel (it uses the Android kernel for Linux) and the vendor’s probably NEVER going to do any work on this - although I was tempted by the Pinebook…