I'm a big fan of mechanical keyboards, and still use the 1984 IBM Model M as my daily driver. The tactile response when pressing the keys helps aid in day-to-day typing, and the durability is unmatched.
Late last year, I reviewed the Tesoro Excalibur, a mechanical keyboard with a single backlight. The keyboard received high praise, but the software didn't allow users to light up individual keys and, of course, it had the same colored LED lighting up every key. At the time, Tesoro promised they would be releasing a full RGB keyboard in the near future. That time is now, and the product is called the Excalibur Spectrum.
Physically, the keyboard is extremely similar to the original Excalibur, so much so that I highly recommend you read the original review. Go ahead, I'll wait.
From a purely physical perspective, there aren't very many differences between the original Excalibur and the Excalibur Spectrum. The keyboard is just as solid as the original, has the same rubber mats on the feet to prevent slipping, and the same strong keys. There's a few minor improvements, such as wrapping the USB cable in a mesh and using a gold USB connector. Then there's a few cosmetic changes, such as moving the controls to modify the brightness and mode from the keypad to the arrow keys, and the company name on the space bar has been replaced with a long line. Other than that, you'd be hard pressed to tell the difference between the Excalibur and the Excalibur Spectrum if someone handed them both to you.