This is just my opinion from having actual experience from using these items:

Smc 6s 4300 - purchased (3) of them for my buggy because I run a 1350kv motor. 2 have dead cells and one is super puffed, last one still working but there's always a cell that is a few volts behind after full balance

Maxamps 6s 4000 - have (3) as well. have changed absolutely nothing in my buggy except for the batteries. These batteries balanced out every time and go into storage mode every time. They do have more punch. These are in soft packs and no sign of puff.

I use the same methods to store and balance so everything remained equal Throughout. Race 3 times a week, Friday, Saturday and Sunday and medium to large tracks. Even wicked weekend and fall brawl.