CLC bio’s de novo assembler is proprietary, fast, smaller ram (48GB) which beats the 256GB used by SOAPdenovo. It can process a human genome in just 6 hours. So one beefy workstation can do the job. It is a DBG, but very efficient. It's quality is as good as other DBG tools. It claims to support Illumina, 454, Solid, Helicos and Sanger. In reality, the Solid support is limited to using just mate-paired reads late in the assembly process to resolve some contig issues.