The other two are both IP67/68 rated and produce quality audio both inside and out.
The U11 is starting to receive Oreo today and the XZ1 launched with it!
You see why it's not so simple?
I would say OP5t. The sense UI on HTC is sluggish, and the Sony just doesn't have the battery size or screen size to match the 5t. You're also getting a much better os (my opinion) on the 5t than the other two options.
Sense is anything but sluggish. HTC flagships are as zippy as OnePlus phones! Likewise Sony...
Only thing I hate about the Xperias is the design. Horrendous bezels, they get worse every year. Otherwise, those phones are normally very reliable with software and security updates, and Sony is able to deliver very solid battery life.
The U11 is super zippy, for sure! And I've heard the 5T is also nice and smooth. Difficult choice, for sure! Have you had any luck deciding?
Essential Phone is actually not THAT bad. I did use one for a bit and sent it back, but that was because it did things that bothered me. I could see it being a perfectly fine phone for many people.
Anyways...I have used the U11 and I was so impressed with its screen. But what i didn't like was how chubby it was. I am also not a fan of sense ui.
In the end, just buy them, try them, and send it back if you don't like it.