For me it’s the terms – recently I thought about signing some tracks to Sync Tracks (UK) who are relatively new, but learned they want to take your copyright, and don’t pay any MCPS or license fees. So if they sell your track for a corporate video you get nothing, if they sell your track for something broadcast, they take ALL the license money, and you only get 50% of the performance royalty. Oh, and they don’t pay a fee for taking track on either!