I just used the Z1 for two weeks in Costa Rica.
it is significantly noisier than the AirSense machine I use at home, but I quickly got used to it and slept fine for the entire two weeks. I traveled alone, so I can't say if my travel partner was bothered by the noise. (The noise doesn't seem to come from the machine itself, but rather from the airflow around the mask, which is the same mask I use at home.)
There is a small power supply on the cord that adds a bit of weight and bulk. Not a lot, but it's hard to tell from reading the online info. I'd say all told the entire thing adds about a pound to your luggage.
It comes in a drawstring pouch that makes it easy to keep all the parts together. It fit easily in my carry-on. If you're really tight on space, you could skip the pouch and pack all the components individually.
I definitely recommend this for travel. I previously tried the Apex XT Fit, which is a lot less expensive and has a built-in power supply, but it's bulkier and noisier and the light stays on all night -- I eventually put tape over it -- and I didn't sleep well with it.
By the way, I've also traveled with Provent (https://www.proventtherapy.com/), which weighs next to nothing and takes up almost no room in your luggage. It's expensive (about $70 for a 30-day supply) and not covered by insurance. And it definitely takes getting used to. Some nights I woke up and had to remove it in the middle of the night. But it did work and if you can get used to it and don't mind the cost, it's probably the best choice for travel. You need a specific prescription from your sleep medicine provider. I had a couple left over from my last trip and used them on the plane. Made a big difference.