A lot of discussions on ACA as a policy matter.  I like that because I think that's how it should have been. (Though I admit that I am not an expert on health care/insurance market)
As a legal matter, the decision came out as following:
- Federal "mandate" isn't an acceptable excercise under the Commerce Clause.  The vote here is 5-4 along the ideological line, with the liberals protesting viscerally.  The conservatives endorse "action/inaction" distinction, and this new Commerce Clause theory can potentially curtail the power of federal government dramatically in the future, setting a new standard of review.  However, it is unclear how much it will weigh in the future because Roberts' solo opinion seems to treat it like a dictum, rather than a holding.  Libertarian scholars self-congratulate on this line.
- Roberts accepted the government's alternative rationale of federal taxing power.  Whether a law calls itself a tax or acts like a tax is a different matter, and the federal government has exercised taxing power (tax.. to pay debts.. and welfare of the United States..) on various legislations.  Obamacare can be sustained/understood as a valid exercise of the taxing power granted by the Consitution.  (Here, the holding is 5-4 with Roberts joining the liberals)
- Liberals would rather uphold the law under the Commerce Clause, but they have no problem with upholding it under taxing power since it is an easier-to-meet burden.  Again, Ginsberg's opinion reads almost like a complete dissent against Roberts' opinion, largely ignoring the joint dissenters.
- The other conservative justices would have invalidated the entire statutes.  They endorse the "action/inaction" theory and dispute the taxing power rationale since the law clearly states "mandate" and "penalty," despite  involvement of the IRS.   What's interesting here is that they probe into legislative history in order to support their position that the law wasn't designed as a tax.  (Justice Scalia, being a "textualist," usually despises searching of legislative backgrounds) 
- The principal dissent (co-written by the conservatives) is pretty weak.  This is my personal opinion but it is objective to an extent. (give it a try!)  The opinion is somewhat tedious and very short on citations. That is understandable to a degree knowing that they are advancing a brand-new constitutional theory.
- At the end of the day, there is no controlling/lasting legal precedent except the "action/inaction" distinction that 5 justices seem to endorse.  The decision does, however, uphold the Obamacare which looks to have been the bottom line of Roberts.  Whether the action/inaction theory will last remains to be seen (Scalia himself disputed it as a meaningless distinction in the past), but as long as this decision has a value of stare decisis there will not be "Broccoli Horribles" in the future.