[before answering] I can think so of Samey! She has NO personality without Amy!!! She's a totally useless character, like Zoey without Mike!
I think Amy is the best TD character ever, she has a great temper, she's evil and bossy, she's a strong person and she makes her sister do what she wants in very easy way!
But most important, she never gives up! She showed it on episode 5, where she had her revenge on Samey showing people how strong she is, and how long she would have lasted on the island if Samey didn't cheat in episode 3 (luckily Samey was eliminated in episode 5, she wasn't able to go further without Amy!!!)!
She's like a mix of Heather and Courtney for me.
That's just my opinion, you can think what you want. To be honest, I loved Amy before TDPI started. And I was right.