Just plug in the variables to your equation and derive if the additional 45 cfm is worth the extra X bucks; and the extra 142 - 110 = 32 MPH. I was a little baffled when Ego introduced the 575cfm, because the performance characteristics are very close.
Perhaps a bigger factor would be which kit you are considering, mainly between the 2.5 AH and 5.0 AH battery. If you have a tiny area to blow, then the 2.5 (with either 530 or 575) would suffice, but anything larger would pretty much necessitate the 5.0 AH battery.
The black Friday deal, which expired yesterday was the back pack blower with the 7.5AH battery, for $350.