I was once in the same position not that long ago. I held acceptances to a 5-year PA program (very highly ranked) and a combined medical program. I looked into it and decided that I wanted to pursue MD/DO, no matter how tempting the immediate gratification of being a PA may be.
Obviously, the best part about being a PA is that it's only 5 years (accelerated programs) in comparison to a minimum of 11 for most doctors. However, the first four years are largely yours to explore whatever academic interests you have. Even though I'm a pre-med, I'm majoring in Spanish. This would not have been possible in the 5-year PA program.
Another thing that you must consider is the salary gap between physicians and PA's. In any field of medicine, the average doctor will make two to three times more than the average PA who works in the same speciality. This may not seem like a big deal as 80-100k is a lot of money, but in the end, you may be doing "85%" of the work a doctor does for half of the pay.
Hours also may not be as different as you think. Many PA's on the forums report working similar (if not more) hours when compared to their supervising physicians. I remember a reputable poster stating that in his ER group, PA's are assigned more shifts than physicians. Yet in his group, PA's make 2-3 times less than what physicians make.
I saw you mentioned that you can always go back. That's true, but honestly, will it actually happen? Depending on what science courses your program requires you to take (I know the program I was accepted to didn't require physics or organic chemistry), you might have to go back and complete some basic science courses before you could even apply. Trying to remember other sciences like biology and chemistry might make studying for the MCAT difficult too.
Med school and residency would take a minimum of six (w/ LECOM bridge program)/seven additional years. Let's do the math. If you're a PA-C making $100,000 a year and you miss out on seven years of income, that's a loss of $700,000 and an addition of at least $100,000 of student loan debt. While it isn't impossible to go back to school (several SDN members have), it certainly is not easy.
Autonomy is another point. Although your autonomy greatly varies depending on state laws (i.e. up until a few years ago, DO's in my state couldn't supervise PA's) and your individual experience, you will always have a supervising physician. Unfortunately, this means that technically, you could be a PA-C with 40 years of experience finding yourself supervised by a 29 year-old attending.
One of the coolest things about being a PA is that you can work in any speciality. More recently though, it seems like this flexibility is slowly declining. Right now, PA's and NP's both have residencies in almost every speciality. Not too long ago, SDN freaked out when a DNP dermatology residency popped up in Florida. As these become more commonplace, states/insurance companies might begin to require residencies to new PA's to practice or bill.
So I guess what you really need to consider is if you'd be happy being a PA. If you are looking to simply shortcut becoming a doctor, I wouldn't recommend it as I don't think you'll see yourself being happy as one. If you truly understand the limitations of being a PA and genuinely want to become one, then give it a go. Just know what exactly what you're getting into, either MD or PA.
