Buy a summit. (period) I had an old man, it slid down the tree over 5 times when I was using it, and i was using it right. Bought the summit and never felt safer. First time I climbed in it I climbed up to 25 ft and did not realize it till my bow rope got tight, never was that high in the old man b/c I never felt safe.

all in all, Buy a Summit. I love my viper!