Which in Italian means, roughly, "To translate is to betray." This review speaks entirely to translations, not to Dante, who is for God to review.
John Ciardi's translation is wonderful. To my taste it is the best verse translation we have. Its notes are just adequate. The Italian text is not supplied.
Now, Dante translations come in various schools: original metre, English metre, prose divided as verse, straight prose. Dante's original metre (terza rima) is not at home in English, though Chaucer's (somewhat approximate) first English translation uses it, as does Dorothy Sayers (whose Dantean scholarship is superb when she is not being Lord Peter Whimsy). Her heroic attempt is to my mind a waste of time. Nor, to me, does pure prose (such as the magnificent Singleton, work). The Divine Comedy is a poem, and prose does not follow the climaxes, hesitations, and rythms faithfully enough. So we are left with English metre, and with prose structured as verses (cantos). For readers who know some Italian, or Latin, or even French or Spanish, the latter would be my choice, so long as the Italian is supplied on the facing page--you can then hear Dante's own voice while understanding it. For this I would recommend the Durling translation (Oxford). It is wonderfully done and superbly annotated (though Singleton's notes are even more majestic)--which will deal with the common Dante complaint, "Who are all these people?". If you want to read directly in English verse, Ciardi is your man. Additional reading would be Dorothy Sayers' "Further Readings on Dante" (Harper). Or, buy Ciardi for his verse and Singleton for his notes and Italian text. AND, PLEASE don't read JUST the Inferno. Read Purgatorio and Paradiso too. You must! Inferno is just a part. If you dedicate your life's leisure to this poem you will have made a perfectly sound choice.
A note about Dante's Italian. In the Comedy it is extremely challenging. This is not at all because it is old, nor because it is poetry. Though my own Italian is by no means exemplary, I quite easily read Dante's approximate contemporaries, Ariosto, Tasso (a lovely poet) or even older poets such as the charming lady La Compiuta Donzella. With Dante in the Italian I must have a crib (I use Durling's edition, as above), though I can read it straight from the Italian after I have been through it with English across the page. However, it would be more correct to say that Dante's language is difficult than that his Italian is. The other poets are writing primarily about chivalry, war, and love (Dante, elsewhere, most definitely writes above love--far too much, Beatrice will comment in Heaven). In The Comedy, Dante presents his reader with very knotty thoughts and very unexpected images, out on the far frontiers of language. At one point in the Inferno, among the thieves, he presents souls being eaten by serpents, in effect excreted as serpents, then returning to their own form to be again eaten by serpents. (Hackers beware! God's identity theft is more comprehensive than yours.) The image is exceedingly dense. I have great respect for translators such as Ciardi or Durling who can grasp it in Italian and then present it in English. With all respect for Love, this is just more complex. You really do not quite read Dante unless you read the Italian, but to read the The Comedy in Italian without aid is, undeniably, a test.