Honestly, the Grado and the Alpha are VERY DIFFERENT from each other, to the point where it’d probably be fun to have them both for different types of listening rather than trying to directly compare or replace one with another.
I don’t know that it’s even right to directly compare them, “Sound quality” wise, because they’re trying to do two completely opposite things.
Grado headphones are very open, and very treble-focused. Grado tunes their headphones by ear, and they have a particular sound signature that’s repeated across all their products that’s made for diehard fans of Grado.
The Alpha is super closed-back, and more of a slightly warm/neutral style of sound. It’s trying to split the difference between audiophile/studio-esque headphones and a fun gaming sound.
The Alpha also has a removable cable and the mic for gaming, so its feature set is totally the opposite of what the Grados offer.
Are you using the Grados for gaming? If so, the Alphas will probably sound very closed-in to you at first, even though they have a decent soundstage for a closed back pair. They’re also going to have a lot more oomph in the lower end.
Grado headphones are more of an acquired taste than the HyperX lineup. If you love the sound of your Grados, you might end up hating how the Alphas sound…because they’re much closer to other neutral/warm headphones than the Grado sound signature.
I hope that helps you out! I’d seriously advise that you try the Alpha before ditching your Grados for them, because they’re so different that you might end up hating them. At the very least, buy from a place that has a return policy!