Is computer audio difficult to set up and run?...I don't think so. Can it sound great?...you bet! Can it drive an audiophile crazy with tweaking?...definitely!!
You audition a few transports on your DAC and find the one you like and you're done, except maybe for some digital cable tweaking (congrats on the PWT by the way, many great reviews!).
With computer audio, though, everything seems to impact the sound so the tweaking involves seemingly endless combinations of ripping software (dbpoweramp, EAC, etc.), file formats (wave vs. flac vs. aiff, compressed vs. non-compressed), computer/storage hardware (PC vs. Mac, different hard drives, NAS, etc.), library management software (iTunes, JRiver, Amarra, UPnP options like Asset) playback software (add-ons to iTunes), settings within playback software. You can definitely get a great system going but you've got to have a lot of patience and good support from your local dealer to put the pieces together for a digital front end system that gives you optimal performance. It's a tweaker's paradise or nightmare, depending on your perspective...
Closed systems help make some of these deicisons for you (e.g. Sooloos) to simplify the matter but they can be expensive.
I agree that computer audio (networked or not) will become increasingly popular but it'll be a different world with a more "open source" type of approach that is more akin to the world of computers than traditional audio.