I found this a fine and useful translation to read along side the Latin text of Propertius in the Loeb Classical Library (where the facing translation has as its prime aim to help the reader understand the latin; it gets a little dry). Unfortunately, this Oxford World Classics edition does not contain a facing Latin text, like the Oxford World's Classics edition of Catullus (also translated by Guy Lee). Nonetheless, Lee's introduction has to be one of the most interesting and absorbing introductions around, a far cry from the usual jargon-laden tedium that passes for an intro to most paperback classics nowadays. Lee is good on Propertius life and times, and on what he himself is trying to accomplish in the translation - basically, stay as close to the Latin as possible yet still preserve some style to the English. Lee's translations are always elegant on their own and helpful to the "mature student" teaching himself Latin. Try Guy Lee's translations of the Eclogues (Penguin - with facing Latin) and his Catullus (Oxford World Classics - with facing Latin). For a wonderful, well-written account of Propertius and the other great poets of the Augustan era (Virgil, Horace, etc), seek out Jasper Griffin's Latin Poets and Roman Life; like Guy Lee's introduction, Professer Griffin's book is jargon-free, well-written and extremely absorbing - concentrating all the time on the poetry itself and what it has to say (rather than literay theories, etc).
Propertius' political poetry is entirely superfluous; he is at his best when writing odes to Cynthia. Of course, like all love-elegists, he is highly indebted to Catullus, but still he manages to have a charm and lyricism all his own.