In short, very similar! Corsair clearly designed the HS50 to be a competitor for the Cloud II, and that’s right down to mimicking a nigh-identical sound signature, as I mentioned in the review you’ve commented on.
Rather than just repeat myself and talk in subjective terms, let’s have a look at the measurements from the good folks over at Rtings:
Headphones - 1.2 - Graph
Wireless Earbuds Wireless Bluetooth Noise Cancelling Running Earbuds And In-Ears Gaming Xbox One PS4 True Wireless…
On first glance, they look almost the same! The HS50 is missing the trademark HyperX/Beyerdynamic notch around 4k, which means they sound a little more pushed forward in that range. Their treble peaks are in slightly different places, and their bass emphasis extends a tiny bit more into the upper bass region, giving them some extra boom and thump. Detractors might find them slightly muddier, but I think this bass emphasis is fun for games.
If you’re going purely on sound quality, save the money and get the HS50!
The HyperX model’s big advantages are the accessories package and their trademark soft memory foam used in the ear pads and the headband. I don’t really like the Cloud II surround dongle, but there’s no denying that HyperX’s headsets have top-notch comfort.
Corsair’s model will grab on to your head for the first few days due to its more rigid frame. The Clouds jump up to the next level of comfort from first wear and can disappear on your head.