My two cents...
Swami's is the fastest of all four. It's basically a race without a fee. It draws the best talent around town. Occasionally, you will see Pro Roadies and Triathletes during the off season.
It's also safer than the SDBC A ride in both route, road conditions, and personnel.
SDBC riders constantly jockey for position and has a mix of skill levels and it's not unusual for a bonehead to cause a crash.
I've never ridden with NCCC or Ranchos...