The short answer is much and not too much.
On November 4, 2009, in Rome at St. Peter's, on the Memorial of Charles Borromeo (is the significance of this fact due to his being venerated earlier in England than in other parts of the world?), Pope Benedict XVI presented the Apostolic Constitution Anglicanorum Coetibus. Briefly, it provides a canonical structure within the Roman Catholic Church that "enables former Anglicans to maintain some degree of corporate identity and autonomy with regard to the bishops of the geographical dioceses of the Catholic Church while preserving elements of their distinctive Anglican spiritual and liturgical patrimony."
If that sounds complicated, at least the process of becoming Catholic if you're an Anglican isn't.
Nevertheless, what do I think? For an Anglican who finds himself in hostile territory, alone in the wilderness, starving and wishing he were dead under the shade of a tree (HT 1 Kings 19), then (re)attachment makes obvious sense (assuming the Anglican thinks the Reformation is well-nigh over). Why go it alone?
But many of us are not alone: "Yet I will leave seven thousand people alive in Israel—all those who are loyal to me and have not bowed to Baal or kissed his idol" (v. 18). This remnant (hardly analogous to WWII Japanese soldiers fighting unawares that the war is over) embodies the four marks of the church: one, holy, catholic, and apostolic (insofar as any Christian communion can in this time between the times). What's more, an Anglican parish (we have to speak in terms of individual parishes these days, alas) that incarnates these four marks finds itself in the unique position of embodying an unrivaled Western Orthodoxy (not to be confused with Western Rite Orthodox—those Orthodox churches that have adopted traditional Western liturgies).
Those from an Eastern Orthodox communion may know exactly what I'm getting at (despite their probable disagreement): An Anglican parish that is part and parcel of the one, holy, catholic, and apostolic church is a microcosm of the Western Orthodox church before the Great Schism of the medieval era (as the Roman Church once was—at least more robustly than today)—more so than any transplanted Eastern Orthodox church or Western Rite Orthodox church. It reflects organically what an Orthodox church looks like having germinated in the soil of the West. I'm talking more or less about its indigenous or tribal features, an element of parish life that most Orthodox communions know all too well.
My current response to the Ordinariate, then, is thanks, but no thanks. In this regard, Anglicanorum Coetibus kind of misses the mark (not to mention its seeming underhanded end-around the See of Canterbury). We'll be getting somewhere when the Roman Catholic Church recognizes these faithful Anglican parishes in the same manner that they recognize the Orthodox. For starters, that means recognizing the validity of Anglican orders (Anglican priests entering the Ordinariate are, by all accounts, treated as if they're being ordained for the first time) and thus the sacraments she administers (which must needs lead to intercommunion).
One other factor remains pertinent: if, collectively speaking, a parish or diocese, etc., avails itself to the Ordinariate, that's one thing. A parishioner of the one, holy, catholic, and apostolic church operating under a proper understanding of ecclesial authority will not easily act alone—as a secta una—but will instead trust and obey, seeking first to honor the Christ by honoring his duly appointed ministers, the under-shepherds of our souls.
And all of this, perhaps ironically, reminds me of the grand hope of faithful Anglicanism—its end. "Anglicans may choose to regard the incoherences (yet riches) of their own Church as simply a microcosm of those of Christianity world-wide," wrote Aidan Nichols. "In this case they will argue that Anglicanism has no distinctive contribution to make to the coming Great Church: its destiny is to disappear, its triumph will be its dissolution" (p. xx).