The ASRock X99 Extreme6/3.1 is an excellent motherboard for socket LGA2011-v3 systems; it is robust and very complete. Besides the features offered by the chipset (ten SATA-600 ports and six USB 3.0 ports), which are enough for most users, it brings one SATA Express port and three USB 3.1 ports, which support twice the speed of USB 3.0 ports, including one type C port at the rear panel.
It brings eight memory sockets and three PCI Express 3.0 x16 slots, supporting SLI and CrossFire with up to three video cards, which is also more than most users will need. As an extra, it also brings a POST diagnostics display and on-board power, reset, and clear CMOS buttons.
Other highlights of this motherboard include the audio section, which uses a high-end codec with an outstanding signal-to-noise ratio, the excellent voltage regulator circuit, and an M.2 slot that is compatible with both SATA and PCI Express 3.0 x4 (used by some high-performance SSDs) interfaces.
If you intend to build a robust gaming computer or workstation with an LGA2011-v3 CPU and are looking for an excellent cost/benefit ratio, the ASRock X99 Extreme6/3.1 is an excellent choice.