no bike is 100%, of course. no FS bike is going to be even close to it really.. but you can use a suspension with lockout, and the Fuel EX is very efficient.
I have a 9.5, and I love it. I looked at a 6.5 when I bought mine, and liked that one, too.
I think you'd be pleased with the 7, but in the end that's up to you, and trying it is the best way to know.