The iD100 is in a different league than the DLO Homedock HD. The iD100 bypasses the iPod's internal DAC, and uses a true digital signal from the iPod. The DLO does not bypass the internal DAC, but instead synthesizes a digital signal from the analog signal. The Nuforce iDo seems to extract the digital signal, but lacks a few things the Cambridge offers. The Cambridge actually docks the iPod/iPad, where the Nuforce connects via a cable. They both sync and charge the iPod/iPad, but I believe only the iD100 has a remote. The iD100 also offers coaxial S/PDIF, Toslink and AES/EBU digital outputs, where the iDo only offers Coaxial S/PDIF. The iDo has a built in headphone amp, but I doubt many of us would use it over our higher quality amps very often. And what's the point if you're sending the digital signal to your DAC anyway? The iD100 offers Component, Composite and S-Video output, where there is no video output from the iDo. There is also an IR input for the iD100, should you choose to enclose it your AV cabinet.
The Cambridge does cost $50.00 more than the Nuforce unit, so I guess it's a matter of what features are important to you.