The Cloud II is actually a regular pair of headphones with a 3.5mm wired connection. The USB connection is on an entirely separate little sound card thing that’s included in the box. So you could buy the Cloud II’s, never touch the sound card, and use them with any 3.5mm device you’d like just fine, if you wanted to. I enjoy that flexibility, because I’ve never personally loved the way the sound card sounds.
To that end, you could save a few bucks and just get the Cloud Core, which is essentially the same headset without the USB sound card and with a slightly different headband pad.
As far as isolation goes, the entire Cloud lineup uses passive isolation, so there aren’t any active systems in place in any of them.
They all use nice leatherette pads with decent memory foam, and they all have passive isolation that I’d rank as “slightly above average.” I don’t do any objective measurements of isolation(though sites like Rtings do), but there’s a loud coffee shop near my house. I go there and listen with the headphones for a few hours and that’s how I personally rank stuff.
Does your travel include a lot of flying? If so, you might actually want something with an active noise cancelling system. One of the best cheap options is probably the Sennheiser HD 4.50 BT. In the next price tier, there’s the Bose QC25 and MSR7NC. Above that, there’s also the Bose QC35, the Sony WH1000XM2, and the Sennheiser PXC 550. But those last three cost three times as much as most of the HyperX models.
The vast majority of gaming headsets and headphones use passive isolation. Active systems cost a lot of money to develop, and they’re mostly designed around blocking out plane noises/other droning noises. They can be pretty amazing…but for most folks I think passive isolation is going to be fine. And it’s easier to find a cheap, good-sounding passive model than it is to find a cheap active model.
My personal favorite in the Cloud lineup is the Cloud Alpha. It has the softest ear pads and the cleanest sound, to my ears. And I like the removable cable. But honestly, all of them are pretty good, and fair deals for the price.
I hope that helped you out in some way! Thanks for reading and for the question!