I bought an Azio MK Hue keyboard from Amazon. Have gone through several other keyboards, this features Outemu Brown switches, has superb feedback and is very responsive. It's a mechanical keyboard, and the finish is top notch compared to others in this price category. At the moment, I don't think there's a better option at the 3.5-4K price range.
I've used earlier
1) Microsoft Natural
2) MS Natural 4000 (which died some years ago), so I bought another, because I needed an ergonomic keyboard.
3) After the second one died, decided to purchase a regular keyboard because I did want a backlight, and then bought a Circle Adroit X7C. It has 7 backlight modes and is really good to type on. However it's still a membrane keyboard. The design etc is similar to the more expensive Asus and Coolermaster membrane keyboards, so no point paying additional premium for those brands (unless it's warranty you want).
4) Bought a Logitech G105, but found the keys were very firm for a membrane keyboard and finger fatigue would set in immediately. However, the backlight (only blue color) and the finish of the keyboard was flawless.
5) After doing tons of comparisons and following reviews, I was going to purchase either the Logitech G610 (Cherry MX brown) or the Logitech 810 (Romer G, full RGB), but then came across Azio.
6) This brand had a lot of positive reviews, and decided to take the plunge and bought it off Amazon (Azio MK Hue in blue color).
7) Quality, switch response, and feedback is all superb. You only get one color (white) for the backlight, but that's good enough for me. If you want to explore full RGB, the Azio MKG L80 (with Kailh browns) is available off Amazon for a reasonable price.
Many of these other keyboards feature Kailh blues, not Cherry MX blues, but I've found typing on blues has the loud click and hence have been avoiding those. The browns have an actuation point you can feel, are clicky, but not as loud as the blues. This applies to Outemu, Kailh AND the Cherry MX browns.
