How is it in terms of usability? I read there was support, tried a rockchip sbc and found support lacking. Judging from the functionality of various pine products and support, is this any different?
Really it boils down to specific SoC and even specific device; it is futile to try to generalize too much. But Rockchip has seen steady progress in this front, and I'd assume older devices like rk3399 based ones especially would have pretty solid support.
I have another couple RK3588 and RK3588S boards that I just got and that look promising, but I haven't done all my tests yet.
The closest would probably be the Quartz64 which uses the RK3566. The RK3566 is pretty well supported but it has some quirks since most products just use its big brother the RK3568 instead so most of the dev efforts come from that model instead.
The RK3588 is already used in a handful of pretty popular SBCs (such as the OrangePi5) so despite being newer and potentially having a bit less mature drivers in some areas, it is almost certainly getting way more development attention.