My favorite was made by Loc-on, but I think they must have discontinued it. It is made from tubular aluminum, weighs 20#, and is 12 feet to the seat. I've had it for more than 20 years, and quite a few deer have been killed from it. For stands that I don't move often, I constructed ladder stands with seats and small platforms from treated wood. A few years ago I built a dozen of them and distributed them around my place. I can hunt a different stand every day that way, and not get patterned by the deer as easily. I use a pair of bicycle wheels mounted on a threaded rod to move them around.
If you use wood, use only pressure-treated material, and choose it carefully for straight grain and small knots. Pre-drill all holes and use deck screws made for treated wood. Anything else will be unsafe within a few years.