I've been listening to both for a while (on the Shanling M30) and I'm surprised how similar both are to each other, except for the sub-bass and bass being more prominent on the Stealth, not too much to be overbearing but to my ears, just the right amount to be enjoyable. The notes on the Stealth has more weight to them when compared to the Utopia.
Soundstage was close to equal on both, not too wide and not too intimate, however, since the Stealth's are closed backs, the added isolation and blackness of the background due to lower resonances really shine when comparing them against the Utopia. It's as if you're sitting in a well treated room, listening to your favorite speakers.
Mids also go to the Stealth; vocals and instruments are slightly more natural than the Utopia. On the treble side, both are equally revealing without being sibilant, however, to my ears, I feel the Utopias have slightly better transients and dynamics, but not by much.
If you're used to the Utopia's sound signature, the Stealth wouldn't be much of a departure, but you'll be getting better isolation, lower resonances, better mids and a similar soundstage and treble response.
I think the Stealth's will be a good closed back option for Utopia lovers. The details are there along with the excellent timbre, tonality, separation and imaging.
Hope that helps!
(maybe not for your wallet. )