There seems to be a big follwing with the Bencmark, but an used bechmark usb would set me back 1000 bucks. Tough decision.
That is because it is good value even at that price. You get a great headphone amp as well as a solid preamp. The Benchmark is of a precise nature rather than some warmer flavors that are available, however, perhaps the biggest advantage of the Benchmark is its reputation for jitter immunity - practically speaking (if you believe all the claims and reviews) it means you no longer have to worry too much about the source quality or cabling to the DAC (so it removes unknowns - just plug and play - no worries). The biggest drawback is perhaps the precise sound which some people really don't like (I suspect they prefer a more organic, rich and less detailed sound that can really help make a bad recording sound its best and less like a recording).