As you said the most interesting is the 2U/quad server system, the others aren't anything special (let's see dual socket 4 HD, and single AC PSU, where's the innovation there?) but there is little innovation here since Supermicro has had a similar system for quite some time now
I suppose it may work for shops that can only buy from the "big name" companies. Myself I think SGI Cloudrack is a far more innovative and scalable system. I'm sure DCS can come up with some creative things as well but if you can't buy them(1,000+ minimum order) then what difference does it make.
I think anyone who buys a new 5600 system is a fool as well, given most manufacturers will have two socket 8-core systems coming soon, and dual socket 8 and 12 core Opterons. Unless performance really doesn't matter to you(in which case pick whatever is cheapest), get more cores on the die.