Hi,
NiFe require less electronics (ie. no more than I have now) to look after them, and as you say "Hard to Kill". LiFePO4, on the other hand, require balancing, LVD & HVD, and can be killed easily, though it probably would require the user to be a complete fuc*wit to do that!
I have read that they don't use much water, and electrolyte doesn't need to be changed that often. I will be running them within narrow voltage limits (43-59v), due to my inverter, so they won't be getting overcharged. I may lose some KwH, but shouldn't have water loss problems.
I'll post back when I've got them setup & running, and again later, when I see how they are performing. 12 months use should give me an idea on water usage at least.
dRdoS7
EDIT: I also managed to sneak a WbJr through at the same time. Actually ordered it in advance of buying LiFePO4, and not "really" required now, but I'll be able to monitor usage better now.