They have a heel strap
They lock your feet in tight with very little slippage. They work great for light trail hikes as well.
They don’t have a toe strap
I like to have a full range of motion for all of my toes. When I’m going to be on my feet for a long time, these are my preference for the security and free range of motion for all my toes.
Unlike the Z2’s, the sole is slimmer, so they won’t weight you down.
The one disadvantage to these bad boys is the lack of a toe strap. Now, I know I said earlier that to me it’s an advantage. However, if you’re looking to go on some steeper and tougher terrain, these won’t be the best. The toe strap does help give more added security and reduces the risk of slipping.
I wore them to UCF’s Spirit Splash one year and they helped out a bunch. I got to protect my feet and keep my sandals on at the same time…not to mention they got a much needed cleaning.
I’d suggest wearing them to music festivals like Bonaroo or the Vans Warped Tour. You’ll be outside all day in the blazing hot summer sun. You’re going to want to wear sandals. You always run the risk of losing sandals, but if you have the Z1’s, they’ll provide: comfort, foot support, sole protection, and stay on your feet all day.