You let a rig sit with the battery connected for 4 months and wonder why it died? There are things like the clock and EFI computer that constantly suck on your battery, and will drain it FAAAR past the point even a deep cycle Optima can stand in a month or so.

Yes, Optimas do die. I've killed one red top so far. Got it warrantied and we'll see how long this one lives. But I still wouldn't run anything else: No leaks lying on my side or inverted - which is a priority if, like me, you're frequently a little late with the "grab reverse and stand on it" routine... and they take twice as long to die as any other battery, easily. IIRC they have a 5 year free replacement warranty: But you have to know/prove where you bought it. This is why you keep all the reciepts for your trail rig.