The VIA boards are modular in that there is a dozen+ different configurations. Each of these configurations have different prices and features to go with those prices. SATA RAID / Gb Ether (or 3x Gb ether), Component out, DVI/HDMI out, Fiber audio out, TV decoder, Built In CF Card reader, eSATA, you name it, they got it in some form. Some of their CPU/Board combos don't even need an active cooling solution. The only thing they don't really have is a powerful 3D unit, but if your going to be needing that then your better off getting a stronger rig.
The EPIAs are designed to be application systems. Each would have a different function/purpose and you would built it for. So rather then have a "one platform fits all", they built many different boards to fit different needs. The guy building a linux based firewall doesn't need HD / digital multimedia capabilities, but does need heavy network ability.