This is basically the exact same sandal as the Z/1 version that simply has no big toe strap for added security and stability. Check out that review for all of the pertinent info that relates to both versions Chaco Z/1 Classic.
Otherwise the only difference with this Z//2 version, as mentioned above, is the big toe strap. My first pair of non flip flop sandals was a pair of original Teva's many years ago and they had no toe strap. So when I tried my first pair of Chaco's I stuck with that style. About a year later I was hiking down a steep trail to a new bouldering area in Oregon and my feet started sweating and sliding off the end of the sandal like I was "hanging ten" on a surfboard. But I was not doing it on purpose for style and fun, no I was actually slipping and had to stop to tighten them up and fell behind the pack in my Z/1's. My friends in the pack mostly had either approach shoes or the Z/2 and so I realized then that the funny looking, constrictive looking big toe strap actually had a very important purpose. I have bought only Z/2's ever since and they have proven to be the perfect all around, warm weather shoe for my outdoor and around town lifestyle. If you are not going to be packing heavy loads on steep trails at high speed the more relaxed and less constrictive Z/1 would probably be fine for you.