The cupcake tasted good (Note: Not great but just good) - it had a thin layer of marmalade at the botton so that added to the flavour. And it went well with my Hot Vanilla. But let me just say that I was disappointed with the size. For the price of RM4.50, the cupcakes are really small. Cupcakes at Cupcake Chic are the same price but twice as big with a generous amount of icing.
On the whole, I would say that Wondermilk cafe is a nice place to hang out. They've got an indoor and outdoor area but I suppose judging from the heat these days, you would probably want to sit in :)