There are also a few interesting options in the ~$100 price range.
One example is the new WandPi 8M. It's based on the NXP i.MX8M and has a few key advantages (particularly, true gigabit Ethernet and USB 3.0). I've ordered one myself, but I'm not sure exactly when they're supposed to start shipping.
There's also the x86 based UP boards. They're based on newer Intel Atom SoCs, so my guess is that the out-of-the-box Linux support would be fairly decent.
The NXP chips have the other only open source GPU drivers, with the first being the RPi. If you want to do multi-media and need USB3, this is probably what you want.
The upboards are interesting, some have an FPGA, and some NN processing soon courtesy of Movidious.
The Pine64/Rock64 and Orange Pi are as cheap or cheaper than the RPi, and some Allwinner/Rockchip boards have binary GPU drivers, but really YMMV.
One example is the new WandPi 8M. It's based on the NXP i.MX8M and has a few key advantages (particularly, true gigabit Ethernet and USB 3.0). I've ordered one myself, but I'm not sure exactly when they're supposed to start shipping.
There's also the x86 based UP boards. They're based on newer Intel Atom SoCs, so my guess is that the out-of-the-box Linux support would be fairly decent.