I've done the Swami's and SDBC rides and of the two Swami's is the hardest (probably out of all four rides also) and draws the best talent. So be prepared to get dropped. That being said they do regroup at a church as you come into Escondido.
The SDBC rides tends to be larger in size with not so challenging terrain. But it too has it's fast riders who will set a fast tempo. They also regroup, twice if I am not mistaken.
check out this link to the Socal website that gives you the basic 411 you're probably looking for.
http://www.socalcycling.com/Group%20...GroupRides.htm
good luck
Oh yeah, don't forget to check out the Wednesday Ride that goes from Encinitas up to San Clemente and back thru Camp Pendleton