My only experience is with Summit's Viper tree stand, which I bought last year. It's about 21 pounds. Comfortable to sit in. Seems quite sturdy to me. I like the solid feel to the climbing rail. It's fixed in position and doesn't pivot up or down to double as a shooting rail or foot rest. When I reach my tree and take the stand off my back, it takes me about 15 minutes to be up the tree, in position, and pull my rifle up to me. I also considered an API Outdoors stand. They look similar to the Summits, but as I recall, they were made from steel and were quite a bit heavier.
One thing: I wish the safety harness fastened with seatbelt-type buckles instead of those you have to thread through the buckle. I know they make more user-friendly, after-market harnesses, but they're not cheap.