Overall this is a well-considered edition, though Cartlidge takes a libertine approach to the translation of the text, delivering it in extreme colloquialism. The prefatory material is excellent, as is the glossary included in the back. Overall a solid text, and as far as the loose translation, he does admit that if you want to know what the poem says you really have to translate it for yourself, and I appreciated his inclusion of that sentiment.
As for the poem itself--12th? century in origin--it's quite amusing and delightful. The Owl and the Nightingale both argue over who is more useful to man and to God, and it's certainly funny and worthwhile.