If you’re considering the Carbon Superfly then I say go with the Rumblefish. The carbon Superfly has had some issues in the past with breaking near the chainstay.
On another note, how much travel are you wanting from the rear suspension? The hardtail 29ers can give you 2 inches of travel when running tubeless so that’s something to think about money wise. Take the extra bones you save and use it to upgrade components…wheels maybe?