That's an interesting one with the AC/DC outlets and 300 watt inverter.
Let's assume that the price is fairly standard for these things. Doing a quick and dirty comparison, it supplies 100Ah for $1,580. In comparison two Trojan T-105s provide 225Ah at ~$280 for the pair.
But, if its true that these lithium can be safely drawn down 80%, than that battery is equivalent to 160Ah in a regular flooded deep cycle battery (using only 50% capacity).
True, the lithium should last longer over the years but I'm not calculating for that now because we really don't know how many more cycles it has.
If I am doing my math correctly comparing just $/Ah, that lithium is roughly 8 times the cost ($1,580/($280/225)*160) of two 6-volt Trojans. Ouch!
That would make this a very expensive proposition. Of course the lithium in this example provides extra features like the outlets, inverter, maintenance-free, longevity, etc. But still. That's a big price hole to dig out of.
I would need to really think this through (and make sure the "quick & dirty" calculation is correct and include the other benefits of lithium), but it appears to me that the cost of those lithiums currently outweigh their benefits (by a lot) compared to a standard flooded.
(I apologize for the rough price comparison and everyone should feel free to rip it apart