She's definitely trickier, but I think she gets extra bounce after hitting an enemy with her aerial hammer swing? I feel like that's how I remember playing her more, trying to keep bouncing with the hammer to keep speed.

It kinda depends on how you use it. Playing with Amy needs a totally different mindset, it's like returning to Sonic 1 because of the lack of spindash, but also you have an advantage in some Boss Fights. The ideas of her being the "Hard mode" seems accurate.

I like to play with her, in part because is my favorite character overall and in part because a like the challenge.

It's been many years since I played Advance, but I seem to remember her feeling like a bit of a "hard mode". She was definitely the last one I finished before unlocking the true ending, iirc.

I always liked playing as her, but I haven't played since I was a kid.

She's the game's Hard Mode