FireFly Carbon Foam Batteries

[MichiganBill]

HI, First post so pardon me if any format errors. Does anyone have any experience with FireFly carbon foam batteries? In the fall we are going to be doing a trip where will need more amp-hours than the marine deep cycle / starting battery the dealer installed will handle. I've been doing some research and came across the FireFly battery. What I understand: Was developed by Caterpillar for heavy equipment that had long periods sitting with no use. Has been in use in HD equipment world for about 10 years, in Marine usage for several years. Similar to AGM batteries except carbon foam replaces the lead plates. Stated advantages over AGM: 1) can cycle down to about 80% discharge without damage or too low of voltage so more useable amp-hours for same size. 2) Does not sulfate readily so has longer life (several orders of magnitude per claim). 3) very low self discharge when not in use. Compared to Li; 1) lower costs 2) can handle low temperatures and still discharge and charge. Disadvantages: a) more costly per battery than AGM BUT for my Amp-hour needs I can buy only one, with AGM I would need 2 so about same costs. b) Not a huge number of units sold and in use for many years to validate the long life claim. I consulted a friend that has been in the ocean going boat service business for years. He is a fan. I'm wondering if anyone in MOC has experience with FireFly Batteries. I've been an engineer too many years to put much faith in data on a sales website.