Blurs come in s30v (and recently in zdp 189, which is IMO even more high end, but also has better edge retention - read: harder to sharpen), which is high end steel...definitely something I'd pick over d2 given the option. d2 is tool steel. s30v is specifically manufactured as cutlery steel by Crucible. zdp 189 is also a cutlery specific steel manufactured by Hitachi IIRC. Having said that, I'd pick s30v because it's more user friendly for sharpening IMO. And if you're considering ZT knives...they only come in 154cm (0200 model) and s30v (everything else)...that is until the 2010 models begin showing up. The other Kershaw knives come in a variety of steels, all of which perfectly adequate, though some more robust than others.
Kershaw and ZT have the same quality since ZT is owned by Kershaw (KAI).
EDIT: I can almost see the cogwheels at work in your head. If I had to pick between the Stryker, the 0350, or the Blur, I'd pick the 0350 because of blade steel, grip and finally looks. I'm not a fan of grip tape (Blur).
EDIT 2: Blurs also come in 154cm now.