I've had this K70 RGB keyboard for a few years now. Though it is marketed as a gaming keyboard and I don't really game all that much anymore, I love the feel of mechanical keyboards. I haven't timed myself but it feels like I can type much faster and with fewer mistakes.
I also like lots of blinking lights. However, I like them even more when they convey useful information. This brings me to some of my criticisms of this device. Don't get me wrong, purely as a keyboard it is awesome. However, the software (iCUE and whatever came before it) are really utter crap. It's a resource hog for what it does, has minimal functionality (compared to what it seems like it should be able to do), is unintuitive and of questionable reliability (periodically losing the keyboard for instance).
I mostly use the keyboard lighting functionality so I can't speak much to how it works with other corsair devices. The lighting functionality does allow for various custimizations but it isn't really that intuitive. I use the "rain" effect with purple and green to give a sort of Matrix-like effect to my keyboard. Then I added another effect to light the keys in a wave from where I type...a random color with each key press just for some variety. Also a pretty neat effect. You can also select which keys your selected effects apply too which is also pretty neat...but again, not all that intuitive. For those that don't want to pick something basic but are too lazy to create their own effects, there are ton of already created RGB profiles out there. But...you guessed it...loading them is not all that intuitive either.
What's really missing is a way to associate the lighting with something useful. I would love, for instance, to be able to set up individual keys to indicate things like drive and network activity. It seems like this would be rather trivial for Corsair to implement. There is one somewhat useful indicator in that you can change the color of the keys based on the package temperature of your CPU. There are three ranges so you can set three different colors. I set my space bar to show this. However, I would love to be able to show drive and network activity. Maybe individual keys could be tied into notifications somehow too. Does anybody know of any 3rd party utilities that will do this? Corsair hasn't added features like this yet and I kind of doubt they ever will at this point.
The other negative thing about this keyboard is that it requires two USB ports and will not work with a KVM switch (except possibly in BIOS mode but then the RGB functions don't work). I don't regret my purchase but I really wish the software was better and there were more options to control lighting based on external events. You would think there would be a way to make it work with a KVM too but I'm not as sure about that.
If you don't care about any of those things (which really have absolutely nothing to do with gaming anyway) then this is an awesome keyboard. However, if I ever buy another RGB keyboard, I'll definitely take a closer look at what software is available for that particular brand. Not that I expect anything better really.