Bloomberg is alot like apple - they have a dedicated following who doesn't know that better options exist. Most subscribers are only using the basics, though they swear that they can't live without it. For futures trading, their data is mediocre, charting/technicals are poor, trading front end is sub par.
Personally I place little value on news and economic reporting, but if that is something you rely on, you almost need all of the major services, as one will out do the other on many occasions.
Bloomberg api is very good and available as part of the standard service. Surprisingly, very few customers make use of it.