I use a Gorilla, that I bought from Cabela's on sale.
It came with a safety harness, including the lineman's belt.
As to the sticks versus the screw in steps. I use the sticks (2' sections), and around here the screw in steps are not allowed on PUBLIC land.
So, if your going to be hunting PUBLIC land, that may be a consideration to explore, whether they (screw in steps) are legal to use. However I would use whatever you want to if your hunting PRIVATE land.