This ASRock board will not be for everyone, many enthusiast who want to build an X99 system are not looking for a mini-ITX board but there are always some who want a lot of power in a small area.  The form factor limits this board to a single PCIe 3.0 16x port but ASRock did manage to incorporate a half sized mini PCIe 1x slot as well.  Storage options are impressive with a half dozen SATA 6Gbps ports, eSATA, a single SEx port and even a four lane M.2 port.  The dozen assorted USB plugs include a pair which support USB 3.1, and there are two LAN ports, on a board this size there is a lot of potential for peripherals and exotic storage solutions.  Of course overall performance is also key to deciding if this board is worth using and after reading the full review at [H]ard|OCP you will have no doubts this is an impressive motherboard.

"There is a small subset of computer enthusiasts that have been asking for an X99 option in the mini-ITX form factor. Ask and you shall receive, right? ASRock steps up to the plate to provide small form factor enthusiasts with just such a motherboard. We evaluate the X99E-ITX/ac and experience the good, the bad, and the ugly…if any."

Here are some more Motherboard articles from around the web:

Motherboards