Memory Cleaning

is currently disabled on my berry . What are the pros / cons of enabling it?

It doesn't clean much, if you're worried about memory, use the memory opt in my signature.

I beleive that Memory Cleaning you are talking about is ment to clean the active memory, this way if someone was to disassemble your BlackBerry and access the memory, it would not let them. (as it would have been deleted)

Escpecially since the memory cleaning option only really works if Content Protection is enabled.

If you enable it without Content protection enabled memory cleaning will eventually disabled itself.

Here you go:

Memory Cleaning