Is there a listing of gifts you receive by character for the sweeetest friend? Is it different per character or is it just a generic item that everyone receives despite who you give it to? I know it’s probably hard to gather that information since you can only give it to one animal per season. I will update once I make my decision of whom to give it to.
In short, I don't think there's any real difference.
I gave mine to Fang and got a blue flower thingy. It might be like the photos where it appears to be blue for boy characters and pink for girl characters, but I don't fully know. I was excited about the letter you get too from them but it seems more generic than anything.