I have both of these as well. I bought the API 3 years ago, and absolutely fell in love with it. It's fast and easy to set up, quiet and very comfortable. 2 weeks ago, I bought a Viper X5. That API doesn't even compare to the Summit. The Summit is 100% better. Needless to say, my son has inherited a very nice API climbing treestand, because I will never be in any other than my Summit.