One other thing - L/P SmartSide with DiamondKote prefinish is the bomb. It isn't cheap (but neither is good paint) but it has a 35-year warranty, and after having installed a few jobs, I can tell you it is extremely durable. DiamondKote is a trade name proprietary to Wausau Supply Company, most lumber companies buy from them. (A tip - our yard in Grimes sells it, and they deliver for free.)
I agree that DiamondKote is awesome, but homeowners/builders around here rarely use it. I also agree that LP is a superior product, but not by much. I put LP Smartside on my own house. Both will last damn near forever if installed properly. The only serious issue to be aware of when installing LP is expansion. I've seen a lot of jobs where it was installed without proper clearances that had lots of panels pop out from the wall. Can't beat light weight, no silica dust, and less seams with 16' panels though.