a great comparison of LI vs AGM jars

Besides the huge weight advantage, LiFePO4 batteries (the safe Li-Ion batteries) can be left partially charged indefinitely. In fact IIRC they prefer to be stored at around 50% SOC. For those of us with just solar, no generator, that's quite an advantage over AGM when boondocking with uncertain levels of sunshine. As long as you don't drop below 10% or over 90% SOC you are good.

However the cost is still prohibitive for me. Maybe next year?

There's many more yacht owners successfully running LiPO4. But maybe they have more money than most of us ...