A lot of what is available isn't all that amazing, but every now and again I have come across artists that I love - and which I probably would never have encountered otherwise. Mostly these have been electronica artists: Lyua Dust, Airbag Killex, Extronica, Trout and A Brilliant Career for example. I suppose Green Man and Tujiko Noriko could also be filed under this category too.
There have also been a couple of folk/acoustic artists too: for instance Josh Woodward and the Canadian singer-songwriter Christa Couture.
In a couple of cases i've gone on to buy (yes, pay money) for further tracks by these artists. And where i haven't, it's generally because i couldn't find any tracks to buy.
I think i'm going to discover more and more new favourite artists this way.