It's tough to find a decent set of top backlit caps, and these are pretty close to almost being perfect. Upgrading to PBT from ABS makes a world of difference and the sound changes dramatically.
The real issue comes with how the lighting works and the inconsistencies between keys. The number row is very dim while the Enter/backpace/Shift are quite brighter. It's probably due to the placement of the lettering and where it sits over the LED, but it's very jarring at first just how much of a difference there is between cap.
Also, wish it came with a solid spacebar, I don't have an LED under this.
Overall, I really can't complain too hard and if you need a backlit set, this is almost the way to do it.