Aluminum or cast block pros/cons?

[joeydurango]

I've got a line on an aluminum-block 5.3 LS33 (new) for a good price (less than cast!). Could also get the cast block as well. Looking to do a swap into my '72 K10 4x4 along with a 4L60e, for daily driver use. Not into hot-rodding or serious off-roading. I understand the aluminum is lighter - beyond that, what advantages/disadvantages are there between the two block materials? In my industry, aluminum is valued for its light weight, but is known to be less durable over the long haul. Does this hold true for an engine block as well, or are there no real disadvantages to the aluminum block besides the normal price premium?