I had this older digital camera, I took it down south (Sur Baja Mexico) with me on a trip and it got one little splash from some salt water, it wasn't even turned on, a single drop of water entered through the mic hole on the top, and it fried.
I have used all sorts of batteries, and have found the duracell digital ultra batteries hold up the longest, then the Energizers digitals, and if nothing else available energizers industrials work well too.
As for battery leaks, I found that it doesn't matter what brand, if they stay inside too long they will all leak eventually, it's good practice to remove the batteries if something is going to sit around for a while.
I don't have that problem, I use everything battery operated way too much, Costco is a good place to reload on batteries.
I have one of these Petzel head lamps that have 3 leds and an adjustable Zenon light, it takes 4AA's I primarily use just the LED's and usually have to change the batteries every six months (work a lot in the dark), if I use the power beam I will have to change them out much more often.