What is a better pack to purchase and why; A 30 amp dishcharged matched pack or a 35 amp dishcharged matched pack?

from what i have noticed, I bought 2 30 and 2 35 about 2 months ago, the 35 where way better out of the box and for about a month, but now they fell off hard and the 30 are still geting better, This is just what i have noticed with my packs