While I know this post is about going to Malpensa, I also wanted to say generally that Lugano airport is pretty reasonably priced for flights. Much cheaper than you'd imagine for some more commonly traveled routes. If you factor in transportation, time, tolls and parking it takes to go to Malpensa, in the end flying from Lugano airport is pretty comparable.
They are generally reliable, but I missed this once because the bus left a bit early. Get there with ample time.