They made a character out of him, which ranks him higher in my book than movies with dragons who's only emotions are "angry" and "furious". That being said, it's still hard comparing him to other character dragons like Draco and Toothless.
Toothless we can leave out because he's not of a realistic style, so I'll count him in a category of his own.
So it's Smaug vs Draco, I'd give it to Draco, because he simply has more screen-time for us to get to know him, and he still looks awesome after 18 years. I don't know if I'll be able to say the same for Smaug.
But Smaug most certainly is a 9 out of 10, they did a fantastic job and I hope other studios take note of that when making dragons in the future.