I agree with squarre and would add a couple other points.
Majority decisions written by the majority to give the reasoning and support for their decision. As such, the facts, rules, and reasoning included in the opinion are what the they felt necessary to justify the decision. And it is that reasoning, more than the actual decision, that counts. That's why the power to assign the writing of a decision is so important (one of the few real powers of the Chief Justice.)
The arguments the minority supported are often noted and the reasons for dismissing it given, but the full weight of the minority arguement isn't there. Also, the dissent often includes facts the majority thought were irrelevant to its decision. So I don't think it's correct to say you get all the issues, facts, and arguments for both sides in the majority opinion.
Also, an initial majority on a decision can turn into a minority, or be increased, based on drafts of the written opinion. So what you are reading as a dissent may in fact started out as a majority opinion.
Concurrences also can be important as some justices may have agreed with the ruling but disagreed with the majority's reasoning.
As a side bar, a good read on the Supreme Court, and the interactions of the judges as an opinion develops, is "The Brethern" by Bob Woodward and Scott Armstrong. You might try that on a break or summer vacation.
Keep in mind, given the editors don't usually include the dissent/concurrences (or highly edit them,)they must feel there is a good reason to include any dissents/concurrences they do include, and I doubt the reason is to get the book up to 1,400 pages. LOL
I wouldn't spend most of my time on them majority opinion, but definitely spend a little time on dissents and concurrences.