It seems like fury is $100 for 2.6gh, but blade is $200 for 10gh... Wouldn't blade be better?
No. You must consider the watts/ghps ratio. The USB Fury sticks, for example, get about
1watt/ghps rate -- about 2.5ghps @ about 2.5watts. Blades are
much worse. Sure, they get 10ghps. But they
consume 83watts!! That's
8.3watts/ghps!!!
So as mining difficulty increases, there will come a time when it costs more to run the miner than it produces in BTC. That time will come much sooner for a blade than a USB Fury. And even the Fury miners will eventually be obsoleted by the boards that are doing 0.3watt/ghps -- 3.3x as efficient!! When you compare the blades with those devices currently getting 1ghps @ 0.3watts,
the blades require 27.39x as much electricity to do the same amount of work! (3.3 * 8.3) You'll soon see blades being favored by college students and such who don't have to pay for their electricity. And by 'soon', I mean in the next 3-6 months.
To get a better feel for this, I suggest checking out
http://mining.thegenesisblock.com/ and throwing in some of the various mining equipment. Blades just eat way too much power at this stage of the game.