as bias, it is clear that Dryden retains enough perspicacity to recognise some of his weaknesses:

It were an easy matter to produce some thousands of his verses which are lame for want of half a foot, and sometimes a whole one, and which no pronunciation can make otherwise.

Dryden does therefore critically evaluate the weaknesses of Chaucer, pointing out that metrically, he can be considered to be weak in the lack of precision of his verse. However, as he goes on to argue, Chaucer's great strength is in his characterisation, which is so strong that "Not a single character has escaped him" He is so competent in this area that Dryden states he has characterised in his work "the various manners and humours of teh whole English nation in his age." This, according to Dryden, is of far more value than missing the odd half-foot in his meter here and there. Dryden therefore presents a critical view of Chaucer that is not blind to his few inadequacies in his desire to praise him.  

In this Preface Dryden is very clear to draw the points of comparison between Ovid and Chaucer before then going on to state the reasons for his preference for Chaucer. Note, for example, what he says about the two poets and the many similarities that there are between them:

The manners of the poets were not unlike: both of them were well bred, well natur’d, amorous, and libertine, at least in their writings, it may be also in their lives. Their studies were the same, philosophy and philology. Both of them were knowing in astronomy, of which Ovid’s books of the Roman feasts, and Chaucer’s treatise of the Astrolabe, are sufficient witnesses. But Chaucer was likewise an astrologer, as were Virgil, Horace, Persius, and Manilius. Both writ with wonderful facility and clearness: neither were great inventors...

Dryden therefore argues that Ovid and Chaucer can be compared in their manners, their interests and studies and the influence of astonomy upon their work, their style in writing and their habit of taking ideas from other works and buiding upon them to create their own stories rather than inventing new stories themselves. Thus far Dryden is shown to be stating the similarities alone before moving on to the differences. When he does, he draws attention to the following difference in style:

The vulgar judges, which are nine parts in ten of all nations, who call conceits and jingles wit, who see Ovid full of them, and Chaucer altogether without them, will think me little less than mad, for preferring the Englishman to the Roman: yet, with their leave, I must presume to say that the things they admire are only glittering trifles, and so far from being witty, that in a serious poem they are nauseous, because they are unnatural. Would any man who is ready to die for love describe his passion like Narcissus?

Dryden believes that the presence of "conceits" and "wit" in the work of Ovid and their comparative absence in the work of Chaucer are aspects that should not cause the reader to consider Ovid superior to Chaucer. In Dryden's estimation, Ovid's use of conceits and wit are but "glittering trifles" and actually lead to one of Dryden's criticisms of Ovid, as his continual use of such devices actually detract from the serious subject matter that some of his poems describe. Dryden therefore in his criticism gives good reasons for his partiality towards Chaucer and backs it up with solid examples, as the reference to the myth of Narcissus evidences. Although Dryden is definitive in stating his preference for Chaucer, the way in which he does this shows that he is a strong comparative critic. He does not jump staight away to attacking Ovid, but begins by establishing areas of common ground between the two poets, only then moving on to focus on the differences and the reasons for his favour of Chaucer.