At these prices, it really makes sense for VCs to support a few ARM server startups. The margins look exteremely appetizing. ILP performance of ARM 64 bit is catching up to Intel, see Apple's nos vs Haswell.
But core performance is just one part of the architecture, the challenge for ARM vendors will be getting the bus right. Intel is dumping its Ring at higher processor counts,so a mesh/crossbar combo maybe the way to go.
It will be tough to beat Intel in the next 5 years, but even if you get to 70-80% of the performance at hald the price, you can win a lot of sockets.
Also there is no standard chip to chip interconnect. Not sure what ARM's strategy is for multi-socket. I guess they want to currently want to focus on single socket micro-servers.
The RIO consortium is evagelizing SRIO for this space. Of course AMD with ARM+x86 cores and their Freedom Interconnect could be a dark horse (one can only hope !).