I started experimenting with using a PC as a source a number of years ago. I was never thrilled with the sound until about a year or so ago when I was finally able to surpass the sound quality of my good quality SACD player.
There is excellent software and hardware available now that, combined together, can produce extremely good sound. There are a number of ways of going about it these days. I haven't tried the Benchmark DAC, but I would like to.
On the hardware side I wound up building myself a quiet PC and using a Lynx Two B PCI card directly into the amps. On the software side, I use a package called Thuneau Allocator as a crossover between subs and mains, Foobar with Kernel Streaming output or JRiver with ASIO output. The computer becomes even more valuable with an RTA package like True RTA to measure the room response at the listening position. I can then use a high quality software based parametric equalizer such as the one built into Thuneau or Waves to precisely nail the standing wave bumps in the bass region, and tailor the overall response exactly to my preferences. Complete digital room correction systems are also available (but are not particularly easy to use) under both Windows and Linux.
In the end, I believe a well built, well set up computer with a high quality sound card or external DAC is more cost effective than good quality separate components. The Lynx card has sufficient performance so that I was able to sell a very expensive outboard DAC. The VST software plugins have allowed me to remove my Behringer DEQ 2496 from the system, and the Lynx drives my amps well enough that I removed my tube preamp from the system as well. My SACD player presently sits in its box.
It took me a long time to get a system together that outperformed my SACD player, but now have no wish to go back. (Still want to try the Benchmark though).
Alan