Same with me. The triggering issue for me was mentioned above, when I read about the woman who drowned while trying to find her buddy's octo, which had come loose from its retainer.This is why I switched to primary donate. Im fine with the philosophy of traditional donate, and prefer it over primary donate (1 diver switching regs is better than 2 divers having to switch regs).
But I have never been able to find an octo holder that both holds securely and allows for immediate access (If there was one, I'd probably still be traditional donate). I got tired of retrieving and restowing my octo on all my dives. So primary donate it is.