jt,
Like Pinwheel, I have an API Grand Slam Magnum---and I love it! I am not the fondest of heights, but have no problems climbing around in this thing...it's easy to use, makes you feel safe, and when sitting in it , it is very comfortable. Don't have a Summit but have heard nothing but good things about them. I think you would like either one...whichever you choose, MAKE SURE that your bottom section is tied to the top section!!!! My brother wouldn't listen to me----and his feet slipped out of his platform straps and the platform fell all the way to the ground, leaving him hanging on for dear life to the top section. Thank goodness he made it down safely---he listens to me a little more now! Good luck!