The day after launch, I decided I wanted to buy a Switch. Took me till the end of March to finally find one in stock, and it was grey. While I had wanted a neon set, I couldn't wait any longer and decided to just buy the grey one that was available (it sold out just minutes after I placed my order, btw).
I ended up really liking the grey Joy-Cons because they make the system look more discrete when out in public (however little that matters now that the Switch is successful/well-known to the public).
That being said, I bought a pair of Mario Odyssey Red Joy-Cons from Amazon Japan back at Super Mario Odyssey's launch, and they look so gorgeous. They really pop under bright lighting.
Neon red/blue is still really fun, and I wouldn't mind owning a set (honestly, I'd love to own every set), but bottom line is that I wouldn't worry too much about the color that comes in the Switch's box. You can get new colors down the road.