The latter two boards, the B75H2-M2 and B75H2-M3, are micro-ATX format while the B75H2-D is a DTX format introduced by AMD a few years ago. All of these boards focus are cost savings and space savings while maintaining usability of high performance parts.
These ECS B75 motherboards natively support USB 3.0, SATA 3.0 (6 Gb/s), and PCI-E 3.0 (with compatible CPU). While not the focus of the design, you can leverage DirectX 11 for graphics with some Intel CPUs or use the PCI-E slot for any PCI-E graphics solution. You will also find an array of legacy support with headers for LPT (printer port), serial, and COM ports to ensure the business will not have to update the entire office at once.
In addition to the expandability and flexibility, the ECS B75 series comes with Intel’s Small Business Advantage (SBA) software to help manage your entire PC infrastructure. This gives you the ability to control when your PCs turn on and off, as well as providing protection from malware/spyware, automated data backups, and automated maintenance to help small business owners cut unnecessary costs.
It is clear to me what these boards are focused on, but ECS also includes support for their overclocking software, M.I.B III. I don’t see these boards being used for gaming or by PC DIY, but the option is there. If you have a small business with PC needs or if you just want to build a cost efficient gaming rig, the ECS B75 series could be where to start.