As an animator/music supervisor for a mid sized app & game developer, I have to source various sounds & scores for use in our products.
Freesound.org has been great for some basic sounds we've required, but we predominantly use Soughtaftersounds.com due to the music's originality & quality, especialy the custom scores we have commisioned.
In addition, if say, you use one of their tracks and at some point they sell that track as a standalone music release as something like the soundtrack to "your game name" (as in theory it is then the soundtrack to the game, they also include a link back to your game or whatever
it is that your creating. So even more promotion for our app's.
Hope this helps anyone looking for music for their games.