The N5II does match it. Soundstage is equal. But... if I'm honest, the N5II is the tiniest, slightest, wee hair wider. But it's so close as to be practically a tie. The N5II has a little more warmth and body, giving vocals a rounded, more earthy quality. The Opus is drier and thinner.
Other than that, they trade blow for blow in every department of sound I listen for. These are two remarkable players.
Now, the Cayin N5II beats the Opus#1 handily in other areas, like build, aesthetics, and hardware features. Not to mention driving power.
Finding a full upgrade to the Opus#1 will cost you. As it should. The N5II is the better all around player, but it sits squarely in the same tier.