Southwestern, Palomar and EMSTA are all good programs. I don't know much about riverside.
It all boils down to what you are looking for in a school. Palomar has close ties to North County Fire Depts and may lead to a job in that area.
Southwestern is a solid program, the main drawback is that the campus for medic is pretty much on the border.
EMSTA is private, costs more than the other 2, is solid, and offers a student mentor program.
In regards to losing your money, i'm not sure about community college programs, but private schools offer rebates, pro-rated to your progress if you should fail out, as well as the ability to come back and repeat the class only having to pay for the part you haven't taken.
It takes a lot of research, but ultimately, talk to graduates from all the programs, get their likes and dislikes and choose the program that fits you best.
good luck.