The S2 is a bit smaller, and still works great. It's still rather big though, but after having it for 6 months or so, it doesn't feel huge.
It annoys me that they cheaped out with the S3 mini. They could have made an amazing phone that loads of people would have bought, had they made it speedy, but with a smaller screen.
My girlfriend for the Galaxy Ace, but she's a bit disappointed with how slow it is compared to mine. If they could make something that is that size, but runs decently fast, i'm sure it would sell. (Basically the iphone....)