I bought one of the Buddha Machines a while ago. It's a really simple idea, but surprisingly, it doesn't get tiresome even after the novelty wears off. The crackly, mono speaker gives the loops a charming warmth, and adds a little randomness to the sound that makes the repetition more interesting. Also, because it's so easy to move, you can experiment with putting it in different rooms or spaces at different volumes, changing how you perceive the sound. I think making it a physical object was a really smart choice - it brings the machine a lot closer to Erik Satie's idea of "furniture music" than your average ambient music. The music itself is, of course, very good (I think #5 is my favorite).

As a footnote, a while ago I was looking for a ringtone that wouldn't completely embarrass me if it went off in a public situation, and so I put a couple of the fm3 loops on my phone -- my phone speaker is also mono and (very) lo-fi, so it seemed like a natural choice, although I did have to normalize the files in Audacity since my speaker isn't quite as powerful. Unfortunately it turns out my phone is flaky about playing mp3 ringtones (sometimes only the first second or two actually plays), but when I could get them to play they sounded really nice. Someone with a newer model might be able to make this work.