My concerns with the Tyan over the Supermicro is manifold:
First, the AMD chipsets are (arguably) less stable than the Intel.
Second, the AMD processors cost nearly twice as much as the Intel processors and provide no performance benefit over the Xeons (using Linux numbers since Linux is NUMA aware)
Third, Windows is not and for some time will not be NUMA aware, leading to a performance penalty.
Fourth, $300 isn’t enough for a 2U if you want SCA hot swap and enough cooling to survive a fan failure.