On the one hand, the average result is disappointment, but every once in a while you get something you like, and then from there what you get is a new seed for exploration, which from there I get to do a new local hill-climbing exploration of. The rate at which new music is currently coming out exceeds the rate at which I can explore in this manner.
I really like good curators in this regard - labels for instance, there are a lot of those that don't fit into the evil, greedy corporation narrative. Numero Group for instance - a fantastic re-issue label that digs out forgotten, rare or unreleased material and puts it into the spotlight, often for the very first time. Their track record is quite impressing.
However I get your general idea, I use it with my own collection - I actually have one of those smart playlists that picks an album for me I haven't listened to for quite a while. Sometimes you re-discover things you almost forgot about.
That's just not good enough. Whenever your taste isn't bound to certain genres, yet still very specific and hard to put into a score, it gets difficult. Actually I think this is a problem better solved by a small round of enthusiasts, real humans instead of algorithms or crowdsourced data. The latter always seem to fail when your taste ranges from, let's say James Holden (electronic, weird, yet carefully crafted), to Miles Davis, each for very different reasons.
While I buy my music, I enjoy the community over at what.cd which is just as enthusiastic about music as I am. Another community that helps can be found on rdio, which I use for previewing and discovering music - I only follow people with taste I can absolutely agree on there, and I'm really not a social network guy, but the community on rdio is great and knowing what those guys are listening to is very rewarding, and sometimes a good tastemaker.
Yet, I can't say that I'm completely satisfied with those options - there have to be some better places out there.