Advantages of LifePO4 batteries:
3000 to 5000 cycle battery
ability to use a much higher % of the battery capacity, virtually 100%
23 to 30 lbs for a 100 ah battery
very high charge and discharge rates
linear charge rate right up to 100% (instead of 80% with lead acid)
So you wind up with a very compact light weight
battery set. EDIT: Also versatile and very long lasting. Suitable for high amp draws such as inverter loads.