Charlie,
I own both stands. My non typical is before amerstep purchased the company and the Goliath is now into it's second season.
Non typical has made a lot of changes and improvements to this stand which was originally called the Koala Climber, even with these improvements I don't feel it is as solid as the Goliath. I am 6'7" and weigh in around 300lbs., the Summit gives me more room, is easier to climb with and feels more solid once I get up the tree. I do like the straps that attach the non typicals top and bottom section.
I do like the Non Typical hang on models and rapid rail systems. I own two Outfitters and a set of the rails. Both products are top notch.
You cannot shoot while sitting in the Goliath, at least I can't. The bag system and foot rest for the Goliath are smart add on's. The one thing that I had trouble with on the Goliath was the foot bungee system, the new stirrups have cured that problem for me.
If your a big guy and need the extra room I realy reccommend the Goliath. I have been bow hunting for over 35 years and to me it's the best climbing stand that I have ever owned.
Good luck with your choice,
Bmott