I'm going to go against the grain here by saying I prefer Amy. I've only seen Amy twice and received the most amazing teasing, prolonged HE that you could imagine. This girl had me twitching on the bed as she stroked, probed and tickled. Her hands were moving so fast at points that I could have sworn there were two girls touching me, I looked and there weren't, and she kept me right on the edge for quite a while before a very happy end was reached. It was one of the most intense experiences I have ever had. Amazing.
I've seen Helen once and it was all fine but I didn't get to the same peak that I did with Amy. I'm going to concentrate on Amy for now and see how far things can go with her.