Mine is a deLonghi Pinguino. It's supposed to be one of the best and quietest ones. But it still doesn't completely cool the room - I find I want to stand right in front of it, and then it's good! That's why i'm still looking at getting something installed that might be more powerful and get to all the rooms. But that's probably my flat being very hot.
The window seal stuff you can buy online at amazon etc, and you could put it on any windows you want - they kits aren't expensive and you could get one per window. You'd leave the velcro on all the time, really, as it would possibly damage paint/wood to keep peeling it off, but you can if you're careful If you get it the right colour, you don't see it too much . Then you put the seal on that. It's a faff to do it alone, but if you had someone else to hold the bits or if you are taller, it's probably a doddle. You can take the fabric bit down when you're not using it, so that it looks nicer. Frankly ,I don't bother - I just leave the fabric up all summer. You can still close the window around it. It looks a bit tatty, but I pull the blinds down.
You wouldn't want to move the unit around too much, as it's very heavy, but you can - it's on wheels, so if you have a hard floor, it's not too bad. Some of them have water trays to empty etc, but the delonghi one doesn't.
It's fairly noisy; I find it hard to hear on the phone/zoom, but the people on the other end dont' hear it. You wouldn't specially want to watch TV with it on, but you can if you turn it up a bit. You get used to it for sleeping easily, and the white noise is nice.
The Pinguino is one of the most epxensive ones, but I needed a very small one to fit in my flat, which this was. I also got it on an amazon primer or something like that, some price match maybe, which was much less than the normal price. So you might look throughout the year, not just in the summer.