Lets get the big negative out of the way now. The stock pads are simply murder on your ears. The headphones sound better with them than with alternatives, but I could never live with the stock pads, and immediately replaced them. I also tried with Shure 1840 pads, but I don't think they sound as good as with the 1540s, YMMV. The stock headband is also pretty bad, but I've never thought of it as uncomfortable. It's not great feeling in my hands, but on my head I don't really have any complaints.
The highs are super accurate, and clear. Only certain tracks have even the faintest hint of sibilance. I have about 10 tracks in my library that trigger that phenomenon with 1540 pads, and my library is primarily Rock, Rap and EDM. Everything else is just crisp and clean. Sound stage is better than their looks would have you believe. I'd say similar to HD600s. Not SUPER wide, but definitely there.
The included wires are fine. They're not great, I see a lot of folks hating on the proprietary locking connector, but they're fine. They don't actually have the ability to straighten out and just have "kinks" forever. You can replace it with a V-Moda cable if you want, but I don't think it's required.
A down side for some people is you will want an legitimate headphone amp. I use a Schiit Modi 2 and Magni 2 Uber (also fine with a non-uber), and the dial is usually a little past half for my every day listening. When I tried it with a Micca Origen+ I had the dial at 100% just to get something pleasurable to listen to. I'd recommend against using an amp of similar power to the Micca because there's a bit of distortion at the highest gains.
I really can't say a lot except I own and have owned a lot of headphones and these will stick around for quite a while. They're just a joy to listen to.