The literary world is saturated with opinions on Franzen's big novel - it's one reason that I read it, the feeling that if you believe in the importance of literature, then there's an obligation to be on familiar terms with the discourse. And so, a few thoughts...
It's clear that Franzen has lived up to his own philosophy, as expressed in his famous Harper's essay (he's against unnecessarily 'difficult' literary works). Freedom makes for remarkably smooth reading - I don't recall the last time I read a 560 page book so quickly. It's an enjoyable read, to be sure - but for me, its not a surpassing work of art. The comparisons with War and Peace (see: NY Times Book Review) are more than a tad overstated.
To some extent, critics have created the strong reaction to Franzen (though he doesn't go out of his way to cultivate a passive response himself). Rid of all the baggage it comes with though, the weight of expectation, the burden of being held up as the definitive chronicle of our age, Freedom is a solid book. It's ambitious, for sure, and sharply observant of our culture. In many ways its more refined (and more enjoyable) than The Corrections, though it suffers from many of the same problems - deeply unconvincing plot elements, for instance. Take note - whenever a key character leaves the US, Franzen is headed for trouble.
For me though, what's most lacking is any great sense of style. It doesn't read as an artful book, and though you can argue that transparency represents it's own stylistic accomplishment, it's one better suited to acting than it is to literature. In this regard, and by most measures of cumulative weight, Franzen lies beyond John Irving, in line with Michael Chabon, but still some distance short of the likes of Roth, DeLillo and McCarthy, et al.