The drawback with using FPGAs compared to commodity processors is that the FPGA market currently does not support using the bleeding edge processes that CPUs are manufactured with. Typically a competitively priced FPGA will be at least one generation behind a CPU. In HPC FPGA's are a plausible improvement, but at a smaller scale the development costs for incorporating a custom firmware for an FPGA into an application are significant. It all really rests on what demand is out there for a particular algorithm to be implemented as a firmware for an FPGA. FPGAs have limited floating point resources, for example the largest Xilinx Virtex 6 FPGA has about 2000 25 x 18 floating point units.