I haven't gotten the unicorn mount yet, but I am really looking forward to it! The mane and tail are a bit funny looking, but overall, I am just thrilled that SE added it. <3 Way cooler than a Goobbue!

And I love the Nightmare idea. I know Yoshi-P said the unicorn was meant as a "bribe" to play healer, but it would be awesome if they added it as another class mount.