The highly talented people at Polygraph, with the help of Kevin Beacham at Rhymesayers, have put together an incredibly in-depth look at labels throughout hip-hop history and how they compare with each other in regards to the performance of their artists on Billboard charts.
The most successful label in hip-hop history, according to the metrics they use, is Def Jam, followed by the mighty Young Money. You can sort that chart by city and look at how NY, LA, New Orleans, Atlanta, San Francisco, and Miami labels stack up against each other.
You can also take a look at the results year by year, starting in 1989, the year Billboard launched their Hot Rap Singles chart.
The charts they made are beautifully rendered and thoughtfully researched, so be sure to check them out.