Almost a decade ago, I started running The Fallen; a game set in my own Cyberpunk world. I created my own mechanics and everything. Considering that the world has demons, angels, and the supernatural, as well as the usual Cyberpunk trappings, I realised what better system to use for it other than BRP. BRP is off the shelf, spilling with these things, ready to go. All I need to do is have one rulebook and I'm away.
I plan to continue my Star Wars campaign, moving from D6 to BRP; rather than D20 Saga Edition. With D20, even though the new Saga Edition rules are flexible to a certain degree, I've found that BRP is better suited. BRP is open ended, and allows the players to develop the skills and abilities they want. In D20, you have to wait to go up a level before you improve, no matter what skills you use or actions you undertake. Plus it's heavily geared towards combat. In BRP, you improve the skills you use, and the system allows for a role-play element to the story to become more central. I know Star Wars is action based, and BRP is rather gritty. But play-testing has gone to show how BRP is rather suited to the setting.