Theme of the post: it all depends on the job.
I've talked with PAs (yes, poster before me, physician assistants) who are doing PC and have 9-5/6ish hours, and I've talked with several PAs who do work more than the docs. A lot of times they are the ones doing weekends and/or call. It really depends on the job. Some places PAs do have more times with patients, some places they are just an accessory to a patient mill. Some PAs have to run EVERYTHING by their SP (supervising physician), most experienced PAs only refer to them infrequently. One of the PAs I shadowed saw her SP once a month (he was still on site, just in a different building). Some surgical PAs will do bilateral surgeries with their SP, usually after completing a surgical PA residency. You CAN do research as a PA, but those opportunities are fewer than in the MD world. Someone mentioned the PA profession being "less stressful," when (CNN Money?) just named it one of the top 8 most stressful jobs. Although I don't place much faith in rankings such as that, yes, there are some jobs as a PA that could be less stressful than certain MD jobs, but some could definitely be more. It really depends on the job.
You're right about being done with school earlier, although it's a tough two years (a couple days off for Christmas and one week off between year one and two is all I'll get). The amount of flexibility though in terms of specialties was the pulling point for me. It is a ton easier as a PA as opposed as an MD.
One con that I don't think has been mentioned: patients not wanting to see you because they don't understand your role...they see "assistant" in your title and think of a medical assistant.
Personally, I had to think long and hard about my decision between MD and PA. Debt was the #1 factor, as I have no financial support from family, undergrad loans, and with no in-state school, would be stuck paying private/OOS tutition (I want to go into primary care and don't want to be forced to specialize to handle debt). #2 was the laterability of the PA profession, #3 was the amount of doctors I talked to who said "YES GO PA," as opposed to not meeting any PAs who were dissatisfied with their choice. Like one person mentioned above, PAs don't really have to deal with malpractice, and also the hassles of managing a business.
It's definitely a tough decision though. I struggled with the fact of why I would go PA when I know I could easily get into med school (based off of my GPA, health care experience, LORs and ECs, and assuming I did well on the MCAT). I came to the conclusion that it's not settling at all, it's a separate profession that does have a helpful place within health care.
If you want to hear pros and cons from people actually working in the PA profession, check out this thread on common myths about being a PA:
http://www.physicianassistantforum.com/forums/showthread.php?t=24088
Good luck with your studies!