Just to be awkward, I'll chip in and say that my shadowing experiences have informed my descision about a medical career a heck of a lot more than my full-time HCA job. Which is sort of the point of doing work experience for a medical school application, really.
I don't care how the medical schools may or may not score it, because I know what I've learned and taken away from the experiences and to me they're invaluable.
My HCA job, on the other hand, consists of running around all day cleaning up faeces, constantly being barked at by patients, relatives and nurses and lots of heavy lifting. Doctors seem to zone out when they see the HCA uniform and the vast majority just look right through you and won't even acknowledge a 'hello'. Apart from seeing that doctors are busy, I don't feel like I've learned an awful lot about doctors in a hospital. However, I've learned loads in terms of generic skills (albeit in a hospital setting) that I could have developed anywhere.