I’ve owned both, multiple pieces. I like Pass Labs allot but ultimately preferred the Sugden iA4 Masterclass - which I did not think would be the case. It’s insanely good. Addictive. I’ve owned allot of gear and I think the Sugden is great gear with no compromises. I would recommend some good horn speakers, maybe even tannoy Cheviots (not horns but wow). I currently have it hooked up to a pair of JBL 4349’s and the soundstage is solid and 3-dimensional. Just insanely tangible. I got the Sugden iA4 as a holdover for a Line Magnetic 845-Premium (Stellar unit), I already have one at another house and liked it so much that I wanted one for my Chicago office. There’s a long wait so I got the Sugden, once again as a holdover... Well it didn’t take long for me to cancel the order for the LM 845-Premium, which is a MAGICAL piece, and decide that the Sugden was easily just as good. I wouldn’t say it bested the LM 845-Premium but I’d say it was equally as enjoyable. Pass is great... but both Sugden iA4 Masterclass and Line Magnetic 845-premium where better. Ive had Mcintosh mc462 with a c2700, Pass Labs INT-250, Primaluna evo 400 separates, Bel Canto, Luxman 590axII, AR GSi75, hegel, golden note... a decent amount of gear. In conclusion it is the Sugden iA4 and LM 845-Premium that are gonna stay.