Bit really wondering about running times, as I know it will be much better than my SLA. wondering about the overall quality
All SLA drop in replacement type LiFePO4 batteries are the same for the most part. There really is not a quality difference, they all are made in china with the same cells and a cheap BMS tossed on top and shipped out. The only difference is that some companies use recycled or used cells or just cheaper quality cells in them that may not last as many cycles. But even if it has the "cheaper" cells, you are talking 1,000 cycles instead of 2,000+. I dont think I will be alive for 1,000 more trips on the ice personally....
You get a decent name behind it for warranty purposes with the marcum, not that Amped wouldn't honor warranty also. A buddy of mine has the brutes and says they work fine for him.
You'll never even come close to using the battery in a day of fishing, so just charge when you get home and it warms up. It should last about 2,000 trips, I assume whoever marcum has contracted to make them in china is using new cells. If not, maybe only 1,000 trips on the ice. There is really nothing to worry about, quality wise.