Tash, Obamacare doesn't go into effect until 2014, so if your sister is still on your parents' insurance, it is of the insurance's own doing, or the doing of the Mass insurance program.
Personally, I think it's a good deal for various reasons. Mostly b/c it regulates insurance companies and prevents them from dumping people when they get sick, prevents them from capping benefits at such a low dollar value that no one would be able to see the end of their healthcare costs, and because it makes women well-checks free. But, it also allows college graduates to get on their feet and land jobs before they have to worry about insurance coverage. The girl who lives across the street from me is 22. She's graduated college and works as a nurse's aide, but the facility she works at does not offer affordable insurance b/c nurse's aides get paid peasant's wages in Iowa... she can't be on her parents' policy b/c she's graduated. She has something going on and is blacking out a lot, for no apparent reason, and she can't see a doctor because she already owes thousands for the testing she's had done so far... which is only a CT scan so far, I believe. So, she's walking around, having unexplained blackouts, and praying to whatever diety that she doesn't black out while driving as she goes to her 12-16 hour a day job as a nurse's aide... I feel badly for her and think this program will help people like her who don't qualify for state aid (Medicaid) or other low cost insurance policies.
Anyhow, like you, I don't like to talk about politics b/c it usually ends badly, but those are my thoughts on the ACA... I truly think it'll be a benefit to those without and will only enhance the benefits of those who have insurance already.