There is one thing that matters the most for both artist and fan, and that's price. Whether it's a choose your amount or a set pricing structure, the bands takeaway is going to be crucial in deciding on a service on both ends of the pay model.
To that end, Bandcamp wins here, taking only the cost of Paypal money transfers out of the bands pockets, while Noisetrade collects twenty percent of the revenue earned, which beats iTunes pricing model significantly. Bandcamp is still a fledgling enterprise, with potential to tax the more popular artists as time goes on -- there is no set plan for this yet, however.
Interface is becoming increasingly important as the Internet shy's away from scrolling pink text and dancing Jesus' and moves toward simple, easy to navigate websites. Again, Bandcamp comes out on top here, offering an artist customizable, clean interface that's a dream to navigate and browse through. You can't search, but you can browse tags including location (10 pages of Colorado bands!).
Noisetrade, as it currently stands, doesn't allow for a cohesive search, and features a bloated, but pretty flipping box-deal as an interface. It probably looked good on paper and would certainly look hot in a Michael Bay movie, but for the purpose of actually finding a track it fails miserably. While neither of these include the obvious need for a search bar, Bandcamp currently does a better job of linking and utilizing tags to bring around new fans.
Finally, audience interaction: Here we have a bit of a draw. Where Bandcamp allows for absurdly detailed stat tracking including how far listeners got through your songs, Noisetrade taps into the social networking vein and forces fans to share contact information before downloading a track. Both sites feature social network sharing, and while it's much more pronounced on Noisetrade, Bandcamp offers more sharing options. We'll call this one even.
When it boils down to it, both sites offer the same basic service: pay-what-you-want price modeling for small indie bands. Though Bandcamp adds the benefit of set pricing per the band's choosing (or alternately, the hassle to fans who were looking for free tracks), where Noisetrade allows fans to tip for tracks or download them free just by sharing some contact info.
Both sites are set to tackle the same problem: The record distributors are dying, but neither really end up being effective yet. Noisetrade doesn't offer enough for bands, whereas Bandcamp offers so much, it'll inevitably fail, since it has no profit model.
So what's best site for bands right now, waiting on the fringe, trying to figure out how to distribute their music? Probably Bandcamp, but Noisetrade is still worth keeping an eye on.