I have used them all you are talking about.
I about lost my life in a Tree Lounge. Those things don't grip for nothing. I slid down a big oak 25 feet as I was climbing up it. I will never, ever recommend a person using this stand.
API is pretty good. I have the older grand slam super mag. It is big and heavy. I leave it out and lock it to trees.
Summit wise, I got the viper and it is ok as long as I don't wear cold weather clothes. If so, it gets really cramped.
I have used all these plus ol man stands, and if I were buying one today, I would get the Treewalker. Hands down the best I have ever been in.
