It's not a one-to-one copy of the DeathAdder, as we often see from low-budget knock-offs. The Castor is decidedly its own mouse, with a unique ergonomic shape. You certainly wouldn't confuse the DeathAdder and Castor if you set them next to each other. But the similarities are apparent as soon as you lay hands on the Castor's silky-smooth frame.
The Castor is a simple six-button mouse—Left, Right, and Middle mouse, two thumb buttons, and then a DPI switcher to the rear of the scroll wheel. For the record, the Castor supports up to 10,000 DPI. I know you were wondering, since Mionix neglected to tack that stat onto the name this time.
The shape is right-hand centric, and reads sort of like a cross between the DeathAdder and Mionix's own Naos 7000. In fact, the Castor is a lot like the Naos 7000, but shrunk down. That makes it a bit more of a jack-of-all-trades mouse—a bit on the small side for palm gripping, a bit large for claw gripping, but the Castor accommodates both pretty easily.
It holds on to some of the Naos's best aspects though, like grooves for your pinky and ring fingers. These aren't just comfortable but functional, giving you a bit of extra control when compared to the DeathAdder's smooth right slope.
And, to my relief, the grooves on the Castor are much less defined than on the Naos 7000. They feel more like a suggestion than anything else—available for palm grippers, but not a hindrance for claw grippers.
The Castor also features the same smooth, soft-touch coating I've come to expect from Mionix. Where the DeathAdder uses Razer's standard lightly-textured plastic, the Castor feels much more luxurious. And again, it's comfort in support of function—the soft-touch texture also provides extra grip, though the tradeoff is (in my experience) a bit more heat/hand sweat.
It's just a Very Nice Mouse, with the aforementioned niceties and then all the standard tricks—a braided fabric cable, lighting in the scroll wheel and logo, and some textured rubber under the thumb.
In reviewing the DeathAdder (again) this year, I noted that it's pretty much the standard by which all other gaming mouses are judged, if only because it's so damned pervasive. The Castor It's the DeathAdder: Director's Cut—the same design philosophy, with a couple of perks.
As such, I'd say the Castor is probably the best “universal” gaming mouse you could find, at the moment. It is understated enough to work in pretty much any game, with pretty much any grip you can imagine, and will still be comfortable.
Does it excel in any one area No, but it doesn't need to. Where another mouse might focus in on a certain aspect and make sure that one aspect is great, the Castor simply makes sure all aspects are pretty damn good.
The one issue Price.
The DeathAdder and Castor actually list for the same price of $70, so that's not the issue. The problem is you can typically find the DeathAdder on perpetual sale for $60 or less, while the Castor has no such discount (at least on Amazon) day-to-day.
Do I think the Castor is worth the extra $10 Absolutely. I like the shape more, I like the finger grooves, I like the DPI switch. But that's ultimately a personal judgment call.
Mionix is a cult favorite for a reason. For a company with so little mainstream recognition, Mionix is putting out some of the best modern gaming mice—over and over and over again. And now they've created one that could actually go mainstream, considering it's their most broad-appeal mouse yet.
I like the Castor a lot. It's simple, it's versatile, and it's just luxurious enough to give it an edge over Razer's similarly-equipped DeathAdder. It might not be the best mouse, but it's a good starting point if you're in the market and need something that does it all.