Soda does provide benefits over other silicia-based media. To be clear, blasting with silicia based media (like regular sand) is what will kill you. Just using a hood won't help, you actually need a fresh air respirator.
The cheaper option is use media that doesn't have any silicia in it. Be informed, as this is a serious issue--search the internet and read up on articles like this one:
http://www.cdc.gov/niosh/silfact1.htmlEven if you use non-silicia blast media (like soda), you still need a decent mask for the airborne particles off the metal (paint, oil, grease).
Some people say soda good, some say soda bad, some say you can't sand blast sheet metal, other's say no problem if you don't over do it. It all seems to depend on who is selling what, if you can believe that!
I bought a regular blaster and got some coal slag based media that is ultra-low silicia based. So far I haven't had time to figure out how to get the blaster working enough to say good or bad. I did do some research on safety issues before I tried it.