I have used a Muro MP3 for several years, and it records in WAV - the line-in is good but the in-built microphone is strictly for grabbing the tune & words - it is small so I carry it at all times and it has grabbed a couple of songs not seen elsewhere.

FWIW I used a camcorder for one very special song. I had it on tape but Joe Latter turned-up at Bromyard and as he is getting on in years I grabbed a video of him singing. Quality is better but cars driving-off don't help.