Opus #2 is considerably more versatile than QA361, but QA361 has more driving power, and more detail. I'd say QA 361 sounds a touch softer and more gentle, where #2 is more organic and has a more analogue-like sound. Battery Life is a touch better on #2. QA361 has both large voltage and large current and can really drive hard-to-drive headphones, whrre #2 is less focused on that. What are you intending on driving from them?