Gotta go with SW.
As much as I like Devy, his stuff that I really like doesn't even come close to SW's stuff that I really like. Yeah, Devy's probably the more skilled singer, but more range =/= better. It's all how you use what you have in a given song, which is one of the reasons Daniel Gildenlow, he tends to overuse his voice, to the detriment of the song at times. Not to say that Devy does this, but it's just a comparison. SW uses what he has to great effect. He can sound a bit whiny at times, but, considering his vocal style, it's surprising to me that that's only happened a few times.
As for technicality, PT/SW has never struck me as an artist that focuses on technicality. It's just not the point. I'd say the same thing for Devy. It's never been about how fast or how technical they can be, they both play for the song.