Rawls' approach (1) accepted the moral legitimacy of classical contract theory; (2) recognized the necessity of balancing competing values, each of them legitimate; and (3) emphasized the importance of accepting for oneself the disciplines one would impose on others. This last, of course, was the point of the "veil of ignorance" in the original position; it was an explicit effort to rule out particularistic, self-interested pleadings.
The reader is left perfectly free to assign a different weight to particular moral judgments and social goals, as conservatives have consistently done. One does not need to kowtow to Rawls' own policy preferences to appreciate his reaffirmation of a classical liberal approach to political philosophy in opposition to the unhinged radicals then in vogue.
Under Rawls' scheme one is perfectly free, for example, to place a higher value on liberty as opposed to equality or security. I think all Rawls would insist upon is that you think through the implications of your answer. The key question remains, "Why should I obey the law?" which very rapidly becomes, "Why should the least advantaged in society obey the law?" Yes, that's a fair question, and if we truly wish to argue that the law is morally binding (as opposed to resting on raw force), we need a compelling answer.
I was extremely gratified to learn what a decent man John Rawls was. Most moral philosophers aren't worth much as philosophers, and some are really vicious specimens of humanity. I studied with some of the best and the worst of the lot; unfortunately, the worst came last. It's nice to be reminded that there are people who not only come up with theories of morality, but who conduct themselves with decency.
Much of the response to John Rawls has had less to do with the man's actual theory, than to his social place within late 20th-century American philosophy, and his use and abuse by other academics. In an obit (on another thread), libertarian Tibor Machan credited Rawls with rescuing American political philosophy. That judgment had never occurred to me, but the moment I read it, I thought, "But, of course!" In the face of the nihilistic desert in which anal philosophy, combined with Marxism, had left American political philosophy, I suppose Rawls gave moral philosophers a giddy, liberated feeling. (Since I had never lived in that desert, had taken my Kant straight-up in West Germany, and would quickly exit the anal desert, I never knew that feeling of liberation.)
In studying Rawls in graduate school, I know that for the prof I studied with, a radical feminist named Virginia Held, the value of any ethical or political theory was limited to its practical, political utility. And I know Held was not alone. That anti-intellectual attitude, and the lack of alternatives, had much to do with Rawls' influence. Note that although Robert Nozick provided an alternative (in 1978, I believe), Nozick was a coward who backed off from his own theory for entirely non-intellectual reasons (his friends in Cambridge didn't like it), and there was no social support among philosophy professors for seriously considering alternative theories.
With that said, Rawls did appear to have problems, when I read him 16 years ago.
The notion that Rawls was a Kantian is deeply problematic: his "Kantian constructivism" looked more pragmatic than Kantian to me. With Kant, there's no room for "constructivism"; moral truth is absolute, certain, and eternal.
The notion of "reflective equilibrium" seemed circular.
Rawls tried to make nice between Kant AND Aristotle. No can do.