I noticed most people replying here are emphasizing differences in pay and authority when it comes to the RPh vs. PA question. While those things are somewhat important (and depend on your personality and preferences in your work environment,) I think the more important aspect of choosing between the two fields relates to the nature of the work performed in each.
As a PA, you will work DIRECTLY with patients. Because your focus will be on diagnosis, it can be a more intensive field as far as critical thinking and problem solving. That's not to say that Pharmacists don't need or use critical thinking/problem solving--they just do so in a different way for a different purpose. The sole purpose of your decisions as a PA will be to accurately diagnose the patient and prescribe the correct medicine. If you wish to interact more directly and personally with people (as in the doctor/patient relationship,) then studying to be a PA (or MD or DO) may be the right path.
As a Pharmacist, you will essentially have a "degree of separation" from the patient (with the exception of some hospital settings.) You will act as the final checkpoint for treating the patient with medicine and can provide counsel to patients with questions, but you won't be required to diagnose a patient's specific condition in any shape or form. This made sense for me, because I actually do want that degree of separation from a patient and only want to be a source of information and control for the meds, not a direct caretaker--(I could NEVER be a nurse!
)
As far as work life, I've read many a time that retail pharmacists are miserable, mistreated, only pill-counters/dispensers, don't get time to counsel patients, yadda yadda yadda. (In my experience, most of it has been true, but I think it really has more to do with the corporate setup for individual pharmacies and how much support staff they allot for their pharmacists. This will obviously vary from store to store, and there are other fields beyond retail you can further explore that are not incorporated, but retail is the fastest growing and most in-demand at the moment.)
As a PA, your worklife will be dictated by the doctor you work for--in that sense, you may have some control over the situation, as in choosing your direct employer (Dr. X who makes his own hours, has his own practice, etc. as opposed to being RPh Z who [if in retail] answers to a corporate honcho.) Again, these are all just hypotheticals--many stores/offices are different depending on location and policy. At this point, I really don't know anything about the long term outlook of growth for RPhs vs PAs, but I do know in the next 5 years, both will be in relatively high demand.
So my point in all this is: if you're considering both fields equally, take a look at all aspects of the worklife, not just money, power, prestige, etc. but also how the work itself will satisfy you, allow for family, professional and personal growth, having a life beyond work, day-to-day activities, and so on.
Hope this helps!