Its data sheet claims 52% efficiency [1], while current generation CCGTs are 60% efficient (e.g. [2]).
Its commercial price is $7,000-$8,000/kW(e) [3]. This is ten times the cost of CCGT power plants, at ~$700-800/kWe (e.g. [4,5]). (This does NOT mean the amortized cents/kWh cost is 10x higher -- most of the final cost is the gas fuel). Ref [5] is particularly relevant, it's financial estimates from California's state energy commission.
edited to add: According to the link [6] in the OP article, the commercial price of the Bloom Box already includes state rebates, and the real cost is twice as high ($14,000-$16,000/kWe). It also reports comparable costs for competing fuel cells ($11,200/kWe for ClearEdge, and $30,000/kWe for Panasonic's really tiny fuel cell).
"A 100-kilowatt Bloom server array costs around $700,000 to $800,000, or $7,500 a kilowatt, after incentives that cover around 50 percent of the costs."
[1] http://www.bloomenergy.com/products/data-sheet/
[2] A modern CCGT turbine: http://www.energy.siemens.com/hq/en/power-generation/gas-tur...
(5,687 BTU/kWh <--> 60.0% efficiency)
[3] http://www.mercurynews.com/breaking-news/ci_16189290
[4] (same turbine as [2]) http://www.power-technology.com/projects/irsching/
[5] CCGT costs in table 14: http://www.energy.ca.gov/2007publications/CEC-200-2007-011/C...
[6] http://www.greentechmedia.com/articles/read/bloom-vs.-solar-...