If you are talking about efficiency, the early bird peek seems to show very efficient use of fuel, which makes sense given the very thick carbon steel and the design layout, as
@Joe Anshien noted. If you are talking about the outside of the grill getting hot, then, yeah, even super thick carbon steel is going to be a good bit hotter than double wall steel like the WSK - or even more so, a ceramic Kamado like the Big Green Egg.
I have already cast my vote, so we will see. A hot grill doesn't bother me here in often very cool Indiana. I use gas all the time, and they are way too hot to touch. That has never been an issue for me, but in a hotter climate I could definitely see it being annoying.
I am mostly intrigued by the fuel door, the extra tight seals, and the hope of making charcoal easy enough that I won't always want to go with pellets or gas. Plus, I like the unique overall look and thoughtful touches that Spider seems to have incorporated. I would never have thought about casting in those reinforcements to the fuel door that Tom Horsman pointed out.
p.s. I will be very curious to see what grates my "regular" shipment grill has. It's hard not to wonder if Tom got special treatment with 304 stainless ones included on his. I will certainly post an honest review of my own.