First of all, the neon colored Joy Cons are absolutely difficult to purchase. The inventory of these items practically don't exist and the only way to luck out buying them is to check the website every day or pay a little more on eBay. Persistence surely pays off because I was able to have my pick of the crop among the colors one afternoon when BestBuy received some inventory of Switch accessories.
Secondly, when you do finally get your hands on a set, the neon colored (Red/Blue combo is what I purchased) is absolutely amazing. The bright colors of the physical product are poorly represented on the cardboard box, but maybe it's a good thing because when you take them out of the box and actually see them with your own eyes of how bright the colors are, then you will surely be more impressed! Immediately, you get a rush to play endlessly all night because the colors make you a "better" player. Who cares about work, right? Wrong. Go to work. Playing the Switch all day doesn't pay your bills.
Last, but definitely not least, if you own the Switch with the neon Joy Cons, you now have 4 different color combinations to play with... Red/Blue, Red/Red, Blue/Red, and Blue/Blue. Whatever combination you fancy, the controllers are top-notch quality, albeit some people face issues with the left Joy Con (I have yet to experience the same, knock on wood). Regardless, if you can get your hands on a pair, then it's definitely worth the purchase.
Rumors have it that Nintendo will release various color combinations in the future. Their "latest" offering in the USA is the ARMS neon yellow Joy Cons, while Japan has already seen the Splatoon 2 neon green/pink versions (Autumn 2017 in USA).