I think some people blew this episode way out of proportion. There were way too many people who were worried that Sheldon would become some sort of sex machine now that he likes kissing Amy. But come on it was one kiss! Sheldon will continue to take baby steps in the relationship and that's great because that's who he is. There was some general disappointment because on the show of all the characters Sheldon comes the closest to being asexual, but if you really watch the show you notice that's not how he identifies. Sheldon himself has said that sexual desire is a cross we all must bare (including himself).
As for this episode. It was great and shocking and so so sweet. Sheldon and Amy both made concessions for each other and found out that they both enjoyed trying something new and Penny and Leonard proved what terrible parents they would make which is always good for a laugh. :)