Sony is 30A. The Efest Purples are 35A.
How low they can handle varies based on what kind of MOD you're using. Are you using variable or mech?
With a mech an fully charged batteries (4.2v) and no voltage drop, you're good with the Efest Purple 35A batteries down to .12Ω and are vaping at 147W, though I'd wouldn't go below .2Ω just to have some headroom. With freshly charged Sony VTC5 30A batteries in a mech the floor is .14Ω (and vaping at 126W), though again, I'd leave some headroom.
On a variable there are too many variables to consider for a simple answer.
I use both, though lately I've been favoring the Efest Purples in 18350, 18500, and 18650 because they offer more amperage headroom than other batteries.