The proposed signal chain with microphone and sound card is as follows:
2 microphones -> mixer -> external soundcard -> notebook.
That means, you use the hard disk of the notebook to store the pretty large wav- file coming from the soundcard via USB connector. The soundcard (I propose to take a cheap 2-channel Soundblaster card, with capability to record with 96kHz/24bit) has a microphone input, but that would work only with dynamic microphones since those microphones don't need an extra power supply.
The quality is really audible much better, if you take a couple of condenser mics, (I use a low cost matched couple TBone SC450, both mics together about 180 Euro, about 200 US-Dollar or whatever). Unfortunately, those mics need a power supply of +48V. Every cheap small mixer (50 US-Dollar perhaps) has such possibility. The output signal of those condenser mics is really large, so no much gain is needed inside the mixer. That's why it can (so I think) be a cheap mixer. The output of the mixer goes in the line-in input of the external soundcard.
A notebook is normally silent enough so that it can be placed in the same room where the piano is during recording. A desktop PC is more immobil, and has fan noise. After the file is captured in the notebook, in can be processed with the software package what is provided by the soundblaster card - in order to downsample to CD quality or to mp3 files.
The recording quality, the above mentioned way, is in my opinion, really better compared to the Edirol. If you listen to Edirol mp3's, there is considerable noise, and with the inbuilt mics, you cannot position the mics on right AND left side of the piano in order to capture bass and treble strings a bit separately in the stereo chain. I think, for mp3 files is the Edirol good enough (listen to Robert's and Chris recordings), for making own CD's I would not use the Edirol.
But the Edirol has the really big charme, to make a recording easy and without arrange the recording stuff with mics etc. Some days ago, I played on a family party. Somehow I liked to record it, but not with those mic stands what looks a bit strange for a party playing. An Edirol can be positioned more discretly. Also for my organ playing, often I wished to simple record it to check my playing. So sooner or later, I will buy such a part in addition to the above mentioned stuff too.