The MSI X99A RAIDER is a sub-$200 LGA-2011 v3 motherboard. I've been using it for almost two months now on one of the daily Linux benchmarking systems and it's been running great.
This shouldn't be a big surprise though given the Intel X99 chipset is now rather mature and in the past I've successfully tested the MSI X99A WORKSTATION and X99S SLI PLUS motherboards on Linux. The X99A RAIDER is lower cost than these other MSI X99 motherboards I've tested, which led me in its direction, and then sticking with MSI due to the success with these other boards and MSI being a supporter of Phoronix and encouraging our Linux hardware testing compared to some other vendors.
The MSI X99A RAIDER supports LGA-2011v3 Xeon / Core CPUs, up to eight DDR4-UDIMM ECC memory modules, USB 3.1 support, M.2 storage, SATA Express + SATA 3.0, Intel Gigabit LAN, and all the other usual features expected from modern motherboards.
I've been running this system with an Intel Xeon E5-2609 v4 Broadwell CPU, 16GB of DDR4-2133 memory, and 256GB Corsair Force LX SSD graphics. The Linux distributions I've run with this setup include Ubuntu 16.04, Ubuntu 16.10, and Intel Clear Linux. Currently this system is used for daily Clear Linux benchmarks on LinuxBenchmarking.com. For those interested there are some benchmarks with this motherboard on OpenBenchmarking.org.
Several weeks into using this system, the MSI X99A RAIDER continues working out great so simply wanted to pass it along in case anyone else is looking for a X99 / LGA-2011v3 motherboard on the lower-cost side at under $200 USD. Those potentially interested can find the motherboard currently in stock at NewEgg.com. Those with any questions about it and Linux can drop by our forums.